Alpha-blockers have been established as medical expulsive therapy for urolithiasis. We aimed to assess the effect of tamsulosin and doxazosin as adjunctive therapy following SWL for renal calculi. We prospectively included 150 patients who underwent up to four SWL sessions for renal stones from June 2008 to 2009. Patients were randomized into three groups of 50 patients each, group A (phloroglucinol 240 mg daily), group B (tamsulosin 0.4 mg once daily plus phloroglucinol), and group C (doxazosin 4 mg plus phloroglucinol). The treatment continued up to maximum 12 weeks. Patients were evaluated for stone expulsion, colic attacks, amount of analgesics and side-effects of alpha-blockers. There were no significant differences between the groups regarding stone expulsion rates (84; 92 and 90%, respectively). The mean expulsion time of tamsulosin was significantly shorter than both control group (p = 0.002) and doxazosin (p = 0.026). Both number of colic episodes and analgesic dosage were significantly lower with tamsulosin as compared to control and doxazosin. Steinstrasse was encountered in 10 (6.7%) patients with no significant difference between the groups. 16 patients on tamsulosin and 21 on doxazosin experienced adverse effects related to postural hypotension. Moreover, 2 (4%) patients in the tamsulosin group reported ejaculatory complaints. In conclusion, adjunction of tamsulosin or doxazosin after SWL for renal calculi decreases the time for stone expulsion, amount of the analgesics and number colic episodes. There was no benefit regarding the overall stone expulsion rate. The side-effects of these agents are common and should be weighted against the benefits of their usage.