OBJECTIVE To determine the comparative efficacy of tamsulosin and nifedipine in medical expulsive therapy (MET) for distal ureteric stones with renal colic. PATIENTS AND METHODS We evaluated the comparative efficacy of tamsulosin and nifedipine in MET in a prospective randomized trial of 3189 outpatients from 10 centres in China. Eligible patients randomly received tamsulosin or nifedipine. Efficacies of the two agents in MET were compared at 4 weeks. The primary endpoint was overall stone-expulsion rate. Secondary endpoints were stone-expulsion time, rate of pain relief therapy, mean analgesic consumption for renal colic recurrence, and side-effects incidence. RESULTS Stone-expulsion rates in the tamsulosin group (group 1) were greater than those in the nifedipine group (group 2; P < 0.01). There was a significant variation in stone-expulsion rates and times between groups 1 and 2 (P < 0.01); with improvements in stone-expulsion rate and time significantly better in group 1 than in group 2. There was a significant variation in the rate of pain relief therapy for renal colic recurrence between groups 1 and 2 (P < 0.01); patients in group 1 required significantly less analgesics than those in group 2 (P < 0.01). There were no statistically significant differences in side-effects incidence between the groups. CONCLUSIONS Administration of tamsulosin and nifedipine in MET was determined to be safe and effective for distal ureteric stones with renal colic. Tamsulosin was significantly better than nifedipine in relieving renal colic and facilitating ureteric stone expulsion.