Gloucestershire settled for a draw at Uxbridge after fellow promotion-chasers Middlesex avoided the follow-on on the final morning.
Chris Rogers ensured Middlesex got the 27 they needed to make the visitors bat again before falling for 148 as his side were dismissed for 325.
Despite holding a first-innings lead of 134, Gloucestershire were in no mood to try and force victory.
They reached 229-8 before shaking hands, Kane Williamson making 73.
Richard Coughtrie, dropped at first slip by England Test captain Andrew Strauss on 0, also contributed 40 and put on 94 for the fifth wicket with Williamson after Gloucestershire had slipped to 65-4.
Tim Murtagh took 3-28 for Middlesex, who remain second in the Division Two table, 32 points behind leaders Northants with a game in hand, while Gloucestershire are a further four points adrift in third.
Middlesex captain Neil Dexter told BBC London 94.9:
"Our main goal this morning was to make sure we got past the follow-on. It was a bit of a disappointing way to end the game but I think with the rain there wasn't much more we could get out of it.
"It's a tough one on him (Andrew Strauss), whatever he's doing at the moment doesn't seem to be going his way. It's not through a lack of trying, it's just one of those things.
"I think there's a lot if pressure on him with the batting at the moment through the press but in his own mind he knows he's still there and definitely a good player."
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