Having led by 123 on first innings, Warwickshire bowled their opponents out for 294 second time round to leave a victory target of 174.
But only Matt Lamb (41, 71 balls and five fours) defied for long as the Bears were all out for 136 and beaten by 37 runs.
Despite the defeat, several players impressed for the home side during the match. With the bat, Alex Thomson scored a first-innings century (103, 171 balls, 16 fours, two sixes) while Alex Mellor hit 70, Andy Umeed 55 and Ed Pollock 51.
With the ball, Sunny Singh harvested match-figures of eight for 205 while Olly Hannon-Dalby took three wickets in each innings.
Tony Frost's side will look to return to winning ways on Friday when they face Somerset in a Second XI Trophy (50 overs per side) semi-final at Moseley (11am).
Warwickshire v Somerset, Second XI Trophy
Warwickshire's Second XI Trophy semi-final versus Somerset at Moseley CC starts at 11am on Friday 15 June.
Entry is completely free for all to enter.Fixtures