It has recently been demonstrated that specific adrenoceptors subtypes (alpha(1A)/alpha(1D)) are prevalent in the distal part of the ureter, a finding supporting the interesting results obtained by different groups with the use of tamsulosin in the treatment of distal ureteral calculi. We performed a prospective randomized study to evaluate the effects of the addition of tamsulosin on our standard pharmacological therapy for the treatment of selected ureteral stones. A total of 64 patients referred to our department for the management of symptomatic ureteral calculi were considered. Patients were randomly divided into two treatment groups: group A (n=32) who received diclofenac (100 mg/daily) plus aescin (80 mg/daily) and group B (n=32) who received the same therapy plus tamsulosin (0.4 mg/daily) for a maximum of 2 weeks. No significant differences were found between the groups for age, gender distribution and mean stone size measured in the single largest dimension at presentation. The stone expulsion rate was 60% (19/32 patients) for group A and 88% for (28/32) for group B with a mean expulsion time of 7.4+/-2.2 (range 3.5-12) and 4.8+/-2.7 days (range 1.8-10.5), respectively. Group B showed a significant advantage in terms of both expulsion rate (P=0.01) and expulsion time (P=0.005). Different analgesics from those used in the standard treatment regimen were required in ten patients in group A (31%) but only three patients in group B (9%). This difference was significant (P=0.003). Hospitalization for recurrent colic was needed in 21% of patients in group A (7/32) and in 9% in group B (3/32) (P=0.01). Only two patients in each group (6%) experienced minor side effects associated with the expulsive therapy. Our data confirm the efficacy of tamsulosin in the treatment of distal ureteral stones up to 1 cm. This selective alpha-blocker should therefore be included in the pharmacological regimen of patients when a conservative approach is considered in the treatment of ureteral lithiasis.