Warwicks chose to bat first and made 155-8 from their twenty overs with Keith Barker top scoring with 35, Darren Maddy making 33, Ant Botha 26 and Neil Carter 21.
Ant Botha also had a good day with the ball taking three wickets against a side for whom Adam Lyth top scored with 34.
Stefan Piolet who has been playing for Binley Road based Coventry & North Warwickshire chipped in with two wickets as did Keith Barker as they restricted the run rate to ensure that Yorkshire could only score 121-9.
On Friday, Warwickshire travel to Northamptonshire for a Twenty/20 game. Play is due to start at 5.30pm and commentary can be heard via the BBC Coventry & Warwickshire website.