diff --git a/src/tools/RotateTool.js b/src/tools/RotateTool.js
index e837b2f6f..fd64b8ec8 100644
--- a/src/tools/RotateTool.js
+++ b/src/tools/RotateTool.js
@@ -57,9 +57,10 @@ function defaultStrategy(evt) {
   const { roundAngles, rotateScale } = this.configuration;
   const { element, viewport, startPoints, currentPoints } = evt.detail;
 
-  const initialRotation = viewport.initialRotation
-    ? viewport.initialRotation
-    : viewport.rotation;
+  const initialRotation =
+    viewport.initialRotation === undefined
+      ? viewport.rotation
+      : viewport.initialRotation;
 
   // Calculate the center of the image
   const rect = element.getBoundingClientRect(element);