diff --git a/shared-types/routes/transactions.ts b/shared-types/routes/transactions.ts
index 476f56d2..7a0fb4f2 100644
--- a/shared-types/routes/transactions.ts
+++ b/shared-types/routes/transactions.ts
@@ -1,4 +1,9 @@
-import { TransactionModel, ACCOUNT_TYPES, SORT_DIRECTIONS, TRANSACTION_TYPES } from 'shared-types';
+import {
+  TransactionModel,
+  ACCOUNT_TYPES,
+  SORT_DIRECTIONS,
+  TRANSACTION_TYPES,
+} from 'shared-types';
 import { QueryPayload } from './index';
 
 export interface GetTransactionsQuery extends QueryPayload {
@@ -34,7 +39,7 @@ export interface CreateTransactionBody {
 export interface UpdateTransactionBody {
   amount?: TransactionModel['amount'];
   destinationAmount?: TransactionModel['amount'];
-  destinationTransactionId?: TransactionModel['id']
+  destinationTransactionId?: TransactionModel['id'];
   note?: TransactionModel['note'];
   time?: string;
   transactionType?: TransactionModel['transactionType'];
@@ -44,3 +49,7 @@ export interface UpdateTransactionBody {
   categoryId?: TransactionModel['categoryId'];
   transferNature?: TransactionModel['transferNature'];
 }
+
+export interface UnlinkTransferTransactionsBody {
+  transferIds: string[];
+}
diff --git a/src/controllers/transactions.controller/index.ts b/src/controllers/transactions.controller/index.ts
index ad45748a..e3e163a8 100644
--- a/src/controllers/transactions.controller/index.ts
+++ b/src/controllers/transactions.controller/index.ts
@@ -2,3 +2,4 @@
 export * from './create-transaction';
 export * from './delete-transaction';
 export * from './update-transaction';
+export * from './unlink-transfer-transactions';
diff --git a/src/controllers/transactions.controller/unlink-transfer-transactions.e2e.ts b/src/controllers/transactions.controller/unlink-transfer-transactions.e2e.ts
new file mode 100644
index 00000000..696c36b2
--- /dev/null
+++ b/src/controllers/transactions.controller/unlink-transfer-transactions.e2e.ts
@@ -0,0 +1,141 @@
+import { TRANSACTION_TRANSFER_NATURE, TRANSACTION_TYPES } from 'shared-types';
+import * as helpers from '@tests/helpers';
+import { faker } from '@faker-js/faker';
+
+describe('Unlink transfer transactions', () => {
+  it('unlink system transactions', async () => {
+    // Firstly create two transfer transactions
+    const accountA = await helpers.createAccount({ raw: true });
+    const accountB = await helpers.createAccount({ raw: true });
+
+    await helpers.createTransaction({
+      payload: {
+        ...helpers.buildTransactionPayload({ accountId: accountA.id }),
+        transferNature: TRANSACTION_TRANSFER_NATURE.common_transfer,
+        destinationAmount: faker.number.int({ max: 1000 }) * 1000,
+        destinationAccountId: accountB.id,
+      },
+      raw: true,
+    });
+
+    await helpers.createTransaction({
+      payload: {
+        ...helpers.buildTransactionPayload({ accountId: accountA.id }),
+        transferNature: TRANSACTION_TRANSFER_NATURE.common_transfer,
+        destinationAmount: faker.number.int({ max: 1000 }) * 1000,
+        destinationAccountId: accountB.id,
+      },
+      raw: true,
+    });
+
+    // Now unlink them
+    const transactions = await helpers.getTransactions({ raw: true });
+    const transferIds = transactions.map((item) => item.transferId);
+
+    const updatedTransactions = await helpers.unlinkTransferTransactions({
+      transferIds,
+      raw: true,
+    });
+
+    // Test that now they're unlinked and not transfer anymore
+    updatedTransactions.forEach((tx) => {
+      const oppositeTx = transactions.find((item) => item.id === tx.id);
+
+      expect(tx).toEqual({
+        ...oppositeTx,
+        transferId: null,
+        transferNature: TRANSACTION_TRANSFER_NATURE.not_transfer,
+      });
+    });
+  });
+  it('unlink external transactions', async () => {
+    // Firstly create external expense + income
+    await helpers.monobank.pair();
+    const { transactions } = await helpers.monobank.mockTransactions();
+    const expenseExternalTx = transactions.find(
+      (item) => item.transactionType === TRANSACTION_TYPES.expense,
+    );
+    const incomeExternalTx = transactions.find(
+      (item) => item.transactionType === TRANSACTION_TYPES.income,
+    );
+
+    // Now create system expense + income
+    const accountA = await helpers.createAccount({ raw: true });
+    const accountB = await helpers.createAccount({ raw: true });
+
+    const [expenseSystemTx] = await helpers.createTransaction({
+      payload: {
+        ...helpers.buildTransactionPayload({ accountId: accountA.id }),
+        transactionType: TRANSACTION_TYPES.expense,
+      },
+      raw: true,
+    });
+
+    const [incomeSystemTx] = await helpers.createTransaction({
+      payload: {
+        ...helpers.buildTransactionPayload({ accountId: accountB.id }),
+        transactionType: TRANSACTION_TYPES.income,
+      },
+      raw: true,
+    });
+
+    // Now link 1 external with 1 system for each type
+    const updatedA = await helpers.updateTransaction({
+      id: expenseExternalTx.id,
+      payload: {
+        transferNature: TRANSACTION_TRANSFER_NATURE.common_transfer,
+        destinationTransactionId: incomeSystemTx.id,
+      },
+      raw: true,
+    });
+    const updatedB = await helpers.updateTransaction({
+      id: incomeExternalTx.id,
+      payload: {
+        transferNature: TRANSACTION_TRANSFER_NATURE.common_transfer,
+        destinationTransactionId: expenseSystemTx.id,
+      },
+      raw: true,
+    });
+
+    // Test that after updation only transfer-related fields were changed for each
+    // transaction
+    expect(expenseExternalTx).toEqual({
+      ...updatedA[0],
+      transferNature: expect.toBeAnythingOrNull(),
+      transferId: expect.toBeAnythingOrNull(),
+    });
+    expect(incomeSystemTx).toEqual({
+      ...updatedA[1],
+      transferNature: expect.toBeAnythingOrNull(),
+      transferId: expect.toBeAnythingOrNull(),
+    });
+    expect(incomeExternalTx).toEqual({
+      ...updatedB[0],
+      transferNature: expect.toBeAnythingOrNull(),
+      transferId: expect.toBeAnythingOrNull(),
+    });
+    expect(expenseSystemTx).toEqual({
+      ...updatedB[1],
+      transferNature: expect.toBeAnythingOrNull(),
+      transferId: expect.toBeAnythingOrNull(),
+    });
+
+    // Now unlink all of them
+    const transferIds = [...updatedA, ...updatedB].map((t) => t.transferId);
+
+    const result = await helpers.unlinkTransferTransactions({
+      transferIds,
+      raw: true,
+    });
+
+    // After unlinking check that transactions now are COMPLETELY SAME
+    [
+      expenseExternalTx,
+      incomeExternalTx,
+      expenseSystemTx,
+      incomeSystemTx,
+    ].forEach((tx) => {
+      expect(result.find((t) => t.id === tx.id)).toEqual(tx);
+    });
+  });
+});
diff --git a/src/controllers/transactions.controller/unlink-transfer-transactions.ts b/src/controllers/transactions.controller/unlink-transfer-transactions.ts
new file mode 100644
index 00000000..c2ef399b
--- /dev/null
+++ b/src/controllers/transactions.controller/unlink-transfer-transactions.ts
@@ -0,0 +1,32 @@
+import { API_RESPONSE_STATUS, endpointsTypes } from 'shared-types';
+import { CustomResponse } from '@common/types';
+import { errorHandler } from '@controllers/helpers';
+import * as transactionsService from '@services/transactions';
+import { ValidationError } from '@js/errors';
+
+export const unlinkTransferTransactions = async (req, res: CustomResponse) => {
+  try {
+    const { transferIds }: endpointsTypes.UnlinkTransferTransactionsBody =
+      req.body;
+    const { id: userId } = req.user;
+
+    if (!transferIds || !Array.isArray(transferIds)) {
+      throw new ValidationError({
+        message:
+          '"transferIds" field is required and should be an array if transferIds.',
+      });
+    }
+
+    const data = await transactionsService.unlinkTransferTransactions({
+      userId,
+      transferIds: [...new Set(transferIds)],
+    });
+
+    return res
+      .status(200)
+      .json({ status: API_RESPONSE_STATUS.success, response: data });
+  } catch (err) {
+    console.log('ERR', err);
+    errorHandler(res, err);
+  }
+};
diff --git a/src/controllers/transactions.controller/update-transaction.e2e.ts b/src/controllers/transactions.controller/update-transaction.e2e.ts
index a1a782ca..7995e93d 100644
--- a/src/controllers/transactions.controller/update-transaction.e2e.ts
+++ b/src/controllers/transactions.controller/update-transaction.e2e.ts
@@ -558,9 +558,5 @@ describe('Update transaction controller', () => {
         expect(txsAfterUpdation[0]).toEqual(tx1);
       },
     );
-    it.todo('test unlinking system transactions');
-    it.todo(
-      'update transfer of two EXTERNAL linked transactions back to their initial state',
-    );
   });
 });
diff --git a/src/routes/transactions.route.ts b/src/routes/transactions.route.ts
index a1923f74..978a7396 100644
--- a/src/routes/transactions.route.ts
+++ b/src/routes/transactions.route.ts
@@ -5,6 +5,7 @@ import {
   getTransactionsByTransferId,
   createTransaction,
   updateTransaction,
+  unlinkTransferTransactions,
   deleteTransaction,
 } from '@controllers/transactions.controller';
 import { authenticateJwt } from '@middlewares/passport';
@@ -19,6 +20,7 @@ router.get(
   getTransactionsByTransferId,
 );
 router.post('/', authenticateJwt, createTransaction);
+router.put('/unlink', authenticateJwt, unlinkTransferTransactions);
 router.put('/:id', authenticateJwt, updateTransaction);
 router.delete('/:id', authenticateJwt, deleteTransaction);
 
diff --git a/src/services/transactions/index.ts b/src/services/transactions/index.ts
index ceb3ceb3..f548db12 100644
--- a/src/services/transactions/index.ts
+++ b/src/services/transactions/index.ts
@@ -5,3 +5,4 @@ export * from './get-transactions';
 export * from './update-transaction';
 export * from './get-by-transfer-id';
 export * from './get-transaction-by-some-id';
+export * from './unlink-transfer-transactions';
diff --git a/src/services/transactions/unlink-transfer-transactions.ts b/src/services/transactions/unlink-transfer-transactions.ts
new file mode 100644
index 00000000..e86787f6
--- /dev/null
+++ b/src/services/transactions/unlink-transfer-transactions.ts
@@ -0,0 +1,62 @@
+import { TRANSACTION_TRANSFER_NATURE } from 'shared-types';
+import { Op, Transaction } from 'sequelize';
+import { connection } from '@models/index';
+import { GenericSequelizeModelAttributes } from '@common/types';
+import { logger } from '@js/utils/logger';
+import * as Transactions from '@models/Transactions.model';
+
+export const unlinkTransferTransactions = async (
+  payload: { userId: number; transferIds: string[] },
+  attributes: GenericSequelizeModelAttributes = {},
+): Promise<Transactions.default[]> => {
+  const isTxPassedFromAbove = attributes.transaction !== undefined;
+  const transaction: Transaction =
+    attributes.transaction ?? (await connection.sequelize.transaction());
+
+  try {
+    const transactions = await Transactions.getTransactionsByArrayOfField(
+      {
+        userId: payload.userId,
+        fieldName: 'transferId',
+        fieldValues: payload.transferIds,
+      },
+      { transaction },
+    );
+
+    const txIds = transactions.map((t) => t.id);
+    await Transactions.default.update(
+      {
+        transferId: null,
+        transferNature: TRANSACTION_TRANSFER_NATURE.not_transfer,
+      },
+      {
+        where: {
+          userId: payload.userId,
+          id: { [Op.in]: txIds },
+        },
+        transaction,
+      },
+    );
+
+    const updatedTxs = await Transactions.getTransactionsByArrayOfField(
+      {
+        userId: payload.userId,
+        fieldName: 'id',
+        fieldValues: txIds,
+      },
+      { transaction },
+    );
+
+    if (!isTxPassedFromAbove) {
+      await transaction.commit();
+    }
+
+    return updatedTxs;
+  } catch (err) {
+    logger.error(err);
+    if (!isTxPassedFromAbove) {
+      await transaction.rollback();
+    }
+    throw err;
+  }
+};
diff --git a/src/tests/helpers/index.ts b/src/tests/helpers/index.ts
index 3b77ccaf..cf305819 100644
--- a/src/tests/helpers/index.ts
+++ b/src/tests/helpers/index.ts
@@ -275,6 +275,34 @@ export function getTransactions({ raw = false } = {}) {
   });
 }
 
+export function unlinkTransferTransactions({
+  transferIds,
+  raw,
+}: {
+  transferIds: string[];
+  raw?: false;
+}): Promise<Response>;
+export function unlinkTransferTransactions({
+  raw,
+  transferIds,
+}: {
+  transferIds: string[];
+  raw?: true;
+}): Promise<Transactions[]>;
+export function unlinkTransferTransactions({
+  raw = false,
+  transferIds = [],
+} = {}) {
+  return makeRequest({
+    method: 'put',
+    url: '/transactions/unlink',
+    payload: {
+      transferIds,
+    },
+    raw,
+  });
+}
+
 export async function getCurrenciesRates({
   codes,
 }: { codes?: string[] } = {}): Promise<ExchangeRates[]> {