diff --git a/netwerk/cookie/nsCookie.cpp b/netwerk/cookie/nsCookie.cpp
index 8b8fa011abe..522b7b9e773 100644
--- a/netwerk/cookie/nsCookie.cpp
+++ b/netwerk/cookie/nsCookie.cpp
@@ -83,6 +83,20 @@ StrBlockCopy(const nsACString &aSource1,
 // check each id to enforce monotonicity.
 static PRInt64 gLastCreationID;
 
+PRInt64
+nsCookie::GenerateCreationID(PRInt64 aCreationTime)
+{
+  // Check if the creation time given to us is greater than the running maximum
+  // (it should always be monotonically increasing).
+  if (aCreationTime > gLastCreationID) {
+    gLastCreationID = aCreationTime;
+    return aCreationTime;
+  }
+
+  // Make up our own.
+  return ++gLastCreationID;
+}
+
 nsCookie *
 nsCookie::Create(const nsACString &aName,
                  const nsACString &aValue,
@@ -111,12 +125,9 @@ nsCookie::Create(const nsACString &aName,
   StrBlockCopy(aName, aValue, aHost, aPath,
                name, value, host, path, end);
 
-  // check if the creation id given to us is greater than the running maximum
-  // (it should always be monotonically increasing). if it's not, make up our own.
+  // If the creationID given to us is higher than the running maximum, update it.
   if (aCreationID > gLastCreationID)
     gLastCreationID = aCreationID;
-  else
-    aCreationID = ++gLastCreationID;
 
   // construct the cookie. placement new, oh yeah!
   return new (place) nsCookie(name, value, host, path, end,
diff --git a/netwerk/cookie/nsCookie.h b/netwerk/cookie/nsCookie.h
index 08a1ca48997..dde12e178de 100644
--- a/netwerk/cookie/nsCookie.h
+++ b/netwerk/cookie/nsCookie.h
@@ -90,6 +90,11 @@ class nsCookie : public nsICookie2
     }
 
   public:
+    // Generate a unique creationID. This will usually be the same as the
+    // creation time, but with a guarantee of monotonicity such that it can
+    // be used as a sqlite rowid.
+    static PRInt64 GenerateCreationID(PRInt64 aCreationTime);
+
     // public helper to create an nsCookie object. use |operator delete|
     // to destroy an object created by this method.
     static nsCookie * Create(const nsACString &aName,
diff --git a/netwerk/cookie/nsCookieService.cpp b/netwerk/cookie/nsCookieService.cpp
index 821fead5301..b5a8fb789bb 100644
--- a/netwerk/cookie/nsCookieService.cpp
+++ b/netwerk/cookie/nsCookieService.cpp
@@ -852,6 +852,7 @@ nsCookieService::TryInitDB(PRBool aDeleteExistingDB)
             "host, "
             "path, "
             "expiry, "
+            "lastAccessed, "
             "isSecure, "
             "isHttpOnly "
           "FROM moz_cookies"), getter_AddRefs(stmt));
@@ -1337,7 +1338,7 @@ nsCookieService::Add(const nsACString &aHost,
     nsCookie::Create(aName, aValue, host, aPath,
                      aExpiry,
                      currentTimeInUsec,
-                     currentTimeInUsec,
+                     nsCookie::GenerateCreationID(currentTimeInUsec),
                      aIsSession,
                      aIsSecure,
                      aIsHttpOnly);
@@ -1454,7 +1455,8 @@ nsCookieService::GetCookieFromRow(T &aRow)
   PRBool isSecure = 0 != aRow->AsInt32(7);
   PRBool isHttpOnly = 0 != aRow->AsInt32(8);
 
-  // create a new nsCookie and assign the data.
+  // Create a new nsCookie and assign the data. We are guaranteed that the
+  // creationID is unique, since we're reading it from the db itself.
   return nsCookie::Create(name, value, host, path,
                           expiry,
                           lastAccessed,
@@ -1784,10 +1786,9 @@ nsCookieService::ImportCookies(nsIFile *aCookieFile)
     if (NS_FAILED(rv))
       continue;
 
-    // create a new nsCookie and assign the data.
-    // we don't know the cookie creation time, so just use the current time;
-    // this is okay, since nsCookie::Create() will make sure the creation id
-    // ends up monotonically increasing.
+    // Create a new nsCookie and assign the data.
+    // We don't know the cookie creation time, so just use the current time
+    // to generate a unique creationID.
     nsRefPtr<nsCookie> newCookie =
       nsCookie::Create(Substring(buffer, nameIndex, cookieIndex - nameIndex - 1),
                        Substring(buffer, cookieIndex, buffer.Length() - cookieIndex),
@@ -1795,7 +1796,7 @@ nsCookieService::ImportCookies(nsIFile *aCookieFile)
                        Substring(buffer, pathIndex, secureIndex - pathIndex - 1),
                        expires,
                        lastAccessedCounter,
-                       currentTimeInUsec,
+                       nsCookie::GenerateCreationID(currentTimeInUsec),
                        PR_FALSE,
                        Substring(buffer, secureIndex, expiresIndex - secureIndex - 1).EqualsLiteral(kTrue),
                        isHttpOnly);
@@ -2119,7 +2120,7 @@ nsCookieService::SetCookieInternal(nsIURI                        *aHostURI,
                      cookieAttributes.path,
                      cookieAttributes.expiryTime,
                      currentTimeInUsec,
-                     currentTimeInUsec,
+                     nsCookie::GenerateCreationID(currentTimeInUsec),
                      cookieAttributes.isSession,
                      cookieAttributes.isSecure,
                      cookieAttributes.isHttpOnly);