diff --git a/CHANGES.md b/CHANGES.md
index 437147741fd1..7e0255b1131d 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -21,6 +21,7 @@ Change Log
 * Fix Firefox WebGL console warnings. [#5912](https://github.com/AnalyticalGraphicsInc/cesium/issues/5912)
 * Fix parsing Cesium.js in older browsers that do not support all TypedArray types. [#6396](https://github.com/AnalyticalGraphicsInc/cesium/pull/6396)
 * Fix flicker when adding, removing, or modifying entities. [#3945](https://github.com/AnalyticalGraphicsInc/cesium/issues/3945)
+* Fixed crash bug in PolylineCollection when a polyline was updated and removed at the same time. [#6455](https://github.com/AnalyticalGraphicsInc/cesium/pull/6455)
 * Fixed Imagery Layers Texture Filters Sandcastle example. [#6472](https://github.com/AnalyticalGraphicsInc/cesium/pull/6472).
 
 ### 1.44 - 2018-04-02
diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index b298aa129217..0d1135678ed0 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -178,3 +178,4 @@ See [CONTRIBUTING.md](CONTRIBUTING.md) for details on how to contribute to Cesiu
 * [Stephen Wiseman](https://github.com/srwiseman)
 * [Gabriel Macario](https://github.com/gabriel-macario)
 * [Jonathan Puckey](https://github.com/puckey)
+* [Mark Erikson](https://github.com/markerikson)
diff --git a/Source/Scene/PolylineCollection.js b/Source/Scene/PolylineCollection.js
index 936744c6ae0b..3404930bb870 100644
--- a/Source/Scene/PolylineCollection.js
+++ b/Source/Scene/PolylineCollection.js
@@ -299,6 +299,12 @@ define([
     PolylineCollection.prototype.remove = function(polyline) {
         if (this.contains(polyline)) {
             this._polylines[polyline._index] = undefined; // Removed later
+
+            var polylineUpdateIndex = this._polylinesToUpdate.indexOf(polyline);
+            if (polylineUpdateIndex !== -1) {
+                this._polylinesToUpdate.splice(polylineUpdateIndex, 1);
+            }
+
             this._polylinesRemoved = true;
             this._createVertexArray = true;
             this._createBatchTable = true;
diff --git a/Specs/Scene/PolylineCollectionSpec.js b/Specs/Scene/PolylineCollectionSpec.js
index ffc2a741e6ea..dfd311ab0030 100644
--- a/Specs/Scene/PolylineCollectionSpec.js
+++ b/Specs/Scene/PolylineCollectionSpec.js
@@ -329,6 +329,20 @@ defineSuite([
         expect(polylines.length).toEqual(0);
     });
 
+    it('removes a polyline from the updated list when removed', function() {
+        var firstPolyline = polylines.add();
+        var secondPolyline = polylines.add();
+
+        firstPolyline.width = 4;
+        secondPolyline.width = 5;
+
+        expect(polylines._polylinesToUpdate.length).toEqual(2);
+
+        polylines.remove(secondPolyline);
+
+        expect(polylines._polylinesToUpdate.length).toEqual(1);
+    });
+
     it('can check if it contains a polyline', function() {
         var polyline = polylines.add();