diff --git a/packages/nodes-base/nodes/SpreadsheetFile.node.ts b/packages/nodes-base/nodes/SpreadsheetFile.node.ts
index ecac7db2cd..26310dfd2d 100644
--- a/packages/nodes-base/nodes/SpreadsheetFile.node.ts
+++ b/packages/nodes-base/nodes/SpreadsheetFile.node.ts
@@ -28,7 +28,7 @@ import {
 function flattenObject (data: IDataObject) {
 	const returnData: IDataObject = {};
 	for (const key1 of Object.keys(data)) {
-		if ((typeof data[key1]) === 'object') {
+		if (data[key1] !== null && (typeof data[key1]) === 'object') {
 			const flatObject = flattenObject(data[key1] as IDataObject);
 			for (const key2 in flatObject) {
 				if (flatObject[key2] === undefined) {