diff --git a/ts/components/session/conversation/SessionCompositionBox.tsx b/ts/components/session/conversation/SessionCompositionBox.tsx
index faf6753d5..a4fcf51f4 100644
--- a/ts/components/session/conversation/SessionCompositionBox.tsx
+++ b/ts/components/session/conversation/SessionCompositionBox.tsx
@@ -918,6 +918,7 @@ export class SessionCompositionBox extends React.Component<Props, State> {
       data: fileBuffer,
       flags: SignalService.AttachmentPointer.Flags.VOICE_MESSAGE,
       contentType: MIME.AUDIO_MP3,
+      size: audioBlob.size,
     };
 
     const messageSuccess = this.props.sendMessage(