Urinary bladder stone is a rare cause of mechanical dystocia. We report a case of mechanical dystocia due to two large vesical calculi. The diagnosis was made during labor when on vaginal examination two large stone of sizes 5x5 cm and 5x4 cm were palpated from the anterior vaginal wall pushing the cervix to one side and obstructing the descent of head. Emergency caesarean section was performed along with simultaneous removal of urinary bladder stones by cystolithotomy. The post operative period was uneventful.