At a gloomy Edgbaston, Glamorgan who needed to win both of their remaining games batted first.
Midway through the ninth over and much to the disgust of an 8,000 strong crowd, the rain came down and the players left the pitch with the score on 79-0.
It was impossible to resume and the match was abandoned with each side taking a point each.
Warwicks play their final home Group game tommorrow night against Northamptonshire. Play is due to start at 5,30pm.