diff --git a/netwerk/protocol/data/src/nsDataChannel.cpp b/netwerk/protocol/data/src/nsDataChannel.cpp
index 34654562b73b..a77afc0fce88 100644
--- a/netwerk/protocol/data/src/nsDataChannel.cpp
+++ b/netwerk/protocol/data/src/nsDataChannel.cpp
@@ -166,7 +166,7 @@ nsDataChannel::ParseData() {
 
     PRUint32 dataLen = PL_strlen(comma+1);
     PRUint32 wrote;
-    writeData *dataToWrite = (writeData*)nsAllocator::Alloc(sizeof(dataToWrite));
+    writeData *dataToWrite = (writeData*)nsAllocator::Alloc(sizeof(writeData));
     if (!dataToWrite) return NS_ERROR_OUT_OF_MEMORY;
 
     if (lBase64) {