diff --git a/dom/console/Console.cpp b/dom/console/Console.cpp
index e5e6c51e864e..174d242ceb1b 100644
--- a/dom/console/Console.cpp
+++ b/dom/console/Console.cpp
@@ -2591,6 +2591,11 @@ Console::MaybeExecuteDumpFunction(JSContext* aCx,
   message.Append(aMethodName);
   message.AppendLiteral(": ");
 
+  if (!mDumpPrefix.IsEmpty()) {
+    message.Append(mDumpPrefix);
+    message.AppendLiteral(": ");
+  }
+
   for (uint32_t i = 0; i < aData.Length(); ++i) {
     JS::Rooted<JS::Value> v(aCx, aData[i]);
     JS::Rooted<JSString*> jsString(aCx, JS_ValueToSource(aCx, v));
@@ -2624,6 +2629,11 @@ Console::MaybeExecuteDumpFunctionForTrace(JSContext* aCx, nsIStackFrame* aStack)
   nsAutoString message;
   message.AssignLiteral("console.trace:\n");
 
+  if (!mDumpPrefix.IsEmpty()) {
+    message.Append(mDumpPrefix);
+    message.AppendLiteral(": ");
+  }
+
   nsCOMPtr<nsIStackFrame> stack(aStack);
 
   while (stack) {
diff --git a/dom/console/Console.h b/dom/console/Console.h
index e2b6226ed58a..f98be7ba1cf5 100644
--- a/dom/console/Console.h
+++ b/dom/console/Console.h
@@ -433,6 +433,7 @@ private:
   nsString mPassedInnerID;
   RefPtr<ConsoleInstanceDumpCallback> mDumpFunction;
   bool mDumpToStdout;
+  nsString mDumpPrefix;
 
   enum {
     eUnknown,
diff --git a/dom/console/ConsoleInstance.cpp b/dom/console/ConsoleInstance.cpp
index 40c52dfa08a0..57243b1d4815 100644
--- a/dom/console/ConsoleInstance.cpp
+++ b/dom/console/ConsoleInstance.cpp
@@ -31,6 +31,8 @@ ConsoleInstance::ConsoleInstance(const ConsoleInstanceOptions& aOptions)
     // For historical reasons, ConsoleInstance prints messages on stdout.
     mConsole->mDumpToStdout = true;
   }
+
+  mConsole->mDumpPrefix = aOptions.mPrefix;
 }
 
 ConsoleInstance::~ConsoleInstance()
diff --git a/dom/console/tests/console.jsm b/dom/console/tests/console.jsm
index 30c38123491a..ad33a973cb8f 100644
--- a/dom/console/tests/console.jsm
+++ b/dom/console/tests/console.jsm
@@ -13,6 +13,7 @@ this.ConsoleTest = {
       consoleID: "wow",
       innerID: "CUSTOM INNER",
       dump: dumpFunction,
+      prefix: "_PREFIX_";
     });
 
     c.log("Hello world!");
diff --git a/dom/console/tests/test_jsm.xul b/dom/console/tests/test_jsm.xul
index 4eba1bd6ccfd..6c1fce9512e8 100644
--- a/dom/console/tests/test_jsm.xul
+++ b/dom/console/tests/test_jsm.xul
@@ -19,6 +19,7 @@ const JSM = "chrome://mochitests/content/chrome/dom/console/tests/console.jsm";
 
 let dumpCalled = 0;
 function dumpFunction(msg) {
+  ok(msg.indexOf("_PREFIX_") != -1, "we have a prefix");
   dump("Message received: " + msg); // Just for debugging
   dumpCalled++;
 }
diff --git a/dom/webidl/Console.webidl b/dom/webidl/Console.webidl
index 2ae8aa0dcff4..7ba99a64be81 100644
--- a/dom/webidl/Console.webidl
+++ b/dom/webidl/Console.webidl
@@ -158,8 +158,8 @@ callback ConsoleInstanceDumpCallback = void (DOMString message);
 
 dictionary ConsoleInstanceOptions {
   ConsoleInstanceDumpCallback dump;
-/* TODO:
   DOMString prefix = "";
+/* TODO:
   DOMString maxLogLevel = "";
 */
   DOMString innerID = "";