diff --git a/change/office-ui-fabric-react-2020-07-17-09-23-46-xgao-details-row.json b/change/office-ui-fabric-react-2020-07-17-09-23-46-xgao-details-row.json
new file mode 100644
index 0000000000000..f066f978bf4d8
--- /dev/null
+++ b/change/office-ui-fabric-react-2020-07-17-09-23-46-xgao-details-row.json
@@ -0,0 +1,8 @@
+{
+  "type": "patch",
+  "comment": "DetailsList: fix exception in DetailsRow when selection is undefined.",
+  "packageName": "office-ui-fabric-react",
+  "email": "xgao@microsoft.com",
+  "dependentChangeType": "patch",
+  "date": "2020-07-17T16:23:46.317Z"
+}
\ No newline at end of file
diff --git a/packages/office-ui-fabric-react/src/components/DetailsList/DetailsRow.base.tsx b/packages/office-ui-fabric-react/src/components/DetailsList/DetailsRow.base.tsx
index ac80a87a7f243..0fede2ef1adbd 100644
--- a/packages/office-ui-fabric-react/src/components/DetailsList/DetailsRow.base.tsx
+++ b/packages/office-ui-fabric-react/src/components/DetailsList/DetailsRow.base.tsx
@@ -74,7 +74,7 @@ export class DetailsRowBase extends React.Component<IDetailsRowBaseProps, IDetai
   }
 
   public componentDidMount(): void {
-    const { dragDropHelper } = this.props;
+    const { dragDropHelper, selection, item, onDidMount } = this.props;
 
     if (dragDropHelper) {
       this._dragDropSubscription = dragDropHelper.subscribe(
@@ -84,12 +84,14 @@ export class DetailsRowBase extends React.Component<IDetailsRowBaseProps, IDetai
       );
     }
 
-    this._events.on(this.props.selection, SELECTION_CHANGE, this._onSelectionChanged);
+    if (selection) {
+      this._events.on(selection, SELECTION_CHANGE, this._onSelectionChanged);
+    }
 
-    if (this.props.onDidMount && this.props.item) {
+    if (onDidMount && item) {
       // If the item appears later, we should wait for it before calling this method.
       this._onDidMountCalled = true;
-      this.props.onDidMount(this);
+      onDidMount(this);
     }
   }