It has been suggested that nitrates are potent smooth muscle relaxants that may reduce pain and facilitate ureteral stone passage; therefore it may be an option for medical expulsive therapy in ureteral stones. In a prospective randomized controlled clinical trial, we evaluated the efficacy of medical expulsive therapy with isosorbide-SR 40 mg in patients with ureteral stones (≤10 mm). The patients with ureteral stones in KUB or urinary tract ultrasonography were randomized to receive methylprednisolone plus celecoxib without (control group), and with isosorbide-SR 40 mg (treatment group) for 21 days. 66 patients [33(50%) in control, 33(50%) in treatment group] were entered randomly to our study. The stone expulsion rate was not significantly different between two groups (54.5 vs. 45.5%) (P = 0.497). The need for surgical procedures were more common in control group within 21 days (9.4 vs. 6.1%) and more common in treatment group after 21 days (33.3 vs. 21.9%) (P = 0.756).Patients in the treatment group experienced more intractable pain (27.3 vs. 6.1%), intractable vomiting (3 vs. 0%) (P = 0.046) and hospitalization (3 vs. 0%) (P = 0.314). Drug side effects including headache and dizziness were more common in treatment group (39.4 vs. 9.1%) (P = 0.004). In our study, the use of isosorbide-SR in treatment group did not improve the stone expulsion rate in patients with ureteral stones (≤10 mm) but developed more side effects. Then it may not an appropriate alternative for medical expulsive therapy. Of course, further trials are recommended.