diff --git a/StompClient.pas b/StompClient.pas
index 56b69887..cb725c18 100644
--- a/StompClient.pas
+++ b/StompClient.pas
@@ -405,6 +405,10 @@ begin
         h := AHeaders.GetAt(i);
         AFrame.GetHeaders.Add(h.Key, h.Value);
       end;
+
+  // If the frame has some content, then set the length of that content.
+  if (AFrame.ContentLength > 0) then
+    AFrame.GetHeaders.Add('content-length', IntToStr(AFrame.ContentLength));
 end;
 
 procedure TStompClient.Nack(const MessageID, TransactionIdentifier: string);
diff --git a/StompTypes.pas b/StompTypes.pas
index bd08fdb0..a16c3088 100644
--- a/StompTypes.pas
+++ b/StompTypes.pas
@@ -63,6 +63,7 @@ type
     procedure SetBody(const Value: string);
     function GetHeaders: IStompHeaders;
     function MessageID: string;
+    function ContentLength: Integer;
   end;
 
   IStompClient = interface
@@ -136,6 +137,7 @@ type
   private
     FCommand: string;
     FBody: string;
+    FContentLength: Integer;
     FHeaders: IStompHeaders;
     procedure SetHeaders(const Value: IStompHeaders);
     function GetCommand: string;
@@ -153,6 +155,7 @@ type
     // otherwise, return Value;
     function Output: string;
     function MessageID: string;
+    function ContentLength: Integer;
     property Headers: IStompHeaders read GetHeaders write SetHeaders;
   end;
 
@@ -286,6 +289,7 @@ begin
   FHeaders := TStompHeaders.Create;
   self.FCommand := '';
   self.FBody := '';
+  self.FContentLength := 0;
 end;
 
 destructor TStompFrame.Destroy;
@@ -319,9 +323,15 @@ begin
     COMMAND_END;
 end;
 
+function TStompFrame.ContentLength: Integer;
+begin
+  Result := FContentLength;
+end;
+
 procedure TStompFrame.SetBody(const Value: string);
 begin
   FBody := Value;
+  FContentLength := Length(TEncoding.UTF8.GetBytes(FBody));
 end;
 
 procedure TStompFrame.SetCommand(const Value: string);