diff --git a/src/TensorNetwork.jl b/src/TensorNetwork.jl
index d5e59b3c6..ad8e601b5 100644
--- a/src/TensorNetwork.jl
+++ b/src/TensorNetwork.jl
@@ -45,7 +45,6 @@ struct TensorNetwork <: AbstractTensorNetwork
         tensormap = IdDict{Tensor,Vector{Symbol}}(tensor => inds(tensor) for tensor in tensors)
 
         indexmap = reduce(tensors; init=Dict{Symbol,Vector{Tensor}}()) do dict, tensor
-            # TODO check for inconsistent dimensions?
             for index in inds(tensor)
                 # TODO use lambda? `Tensor[]` might be reused
                 push!(get!(dict, index, Tensor[]), tensor)
@@ -53,6 +52,12 @@ struct TensorNetwork <: AbstractTensorNetwork
             dict
         end
 
+        # Check for inconsistent index dimensions
+        for ind in keys(indexmap)
+            dims = map(tensor -> size(tensor, ind), indexmap[ind])
+            length(unique(dims)) == 1 || throw(DimensionMismatch("Index $(ind) has inconsistent dimension: $(dims)"))
+        end
+
         return new(indexmap, tensormap, CachedField{Vector{Tensor}}())
     end
 end
diff --git a/test/TensorNetwork_test.jl b/test/TensorNetwork_test.jl
index 6b5448fbb..c30b97b31 100644
--- a/test/TensorNetwork_test.jl
+++ b/test/TensorNetwork_test.jl
@@ -23,7 +23,7 @@
         @testset "TensorNetwork with tensors of different dimensions" begin
             tensor1 = Tensor(zeros(2, 2), (:i, :j))
             tensor2 = Tensor(zeros(3, 3), (:j, :k))
-            @test_skip @test_throws DimensionMismatch tn = TensorNetwork([tensor1, tensor2])
+            @test_throws DimensionMismatch tn = TensorNetwork([tensor1, tensor2])
         end
     end