diff --git a/README.md b/README.md
index d3b130a..666e7ab 100644
--- a/README.md
+++ b/README.md
@@ -84,7 +84,7 @@ Render prop gives you access to three callbacks:
 | Prop                | Type                                    |  Description                      |
 | :------------------ | :-------------------------------------- | :----------------------------------
 | `browseFiles`       | `BrowseFilesParams => void`             | Once executed, file browser will be shown. Useful for file upload buttons. The callback can also accept custom `onSuccess` and `onError` callbacks, that will override the main ones. |
-| `validate`       | `(files: Array<SelectedFile>) => void`             | Enables manual validation of files. Eg. after editing the selected image in an image editor. |
+| `validate`       | `(files: Array<File>) => Array<FileError>`             | Enables manual validation of files. Eg. after editing the selected image in an image editor. |
 | `getDropZoneProps`  | `(additionalProps: ?Object) => Object`  | Props that need to be spread to a drop zone. Additional props can be passed, for example `className` or `style`. |
 | `getLabelProps`  | `(additionalProps: ?Object) => Object`  | Props that need to be spread to your file field's label. Additional props can be passed, for example `className` or `style`. |
 
diff --git a/src/Files.js b/src/Files.js
index 7a47ff5..693f51e 100644
--- a/src/Files.js
+++ b/src/Files.js
@@ -23,7 +23,7 @@ export type FileError = {
         | "multipleMaxSizeExceeded"
         | "multipleMaxCountExceeded"
         | "multipleNotAllowed",
-    file?: SelectedFile
+    file?: SelectedFile | File
 };
 
 export type BrowseFilesParams = {
@@ -73,7 +73,7 @@ class Files extends React.Component<Props> {
         this.id = generateId();
     }
 
-    validateFiles(files: Array<SelectedFile>): Array<Object> {
+    validateFiles(files: Array<SelectedFile> | Array<File>): Array<FileError> {
         const { multiple, multipleMaxSize, multipleMaxCount, accept, maxSize } = this.props;
 
         const errors: Array<FileError> = [];