This study was aimed to evaluate the efficacy of benzbromarone compared to allopurinol in lowering serum uric acid level in hyperuricemic patients with normal renal function (serum creatinine < or = 1.5). The authors conducted a crossover study consisting of two four-week treatment periods of allopurinol 300 mg/day and benzbromarone 100 mg/day separated by a four-week washout period. Fourteen patients with mean age and duration of hyperuricemia of 60.78 +/- 8.62 and 6.93 +/- 3.69 years, respectively, were recruited and all completed our study protocol. This study was a crossover design consisting of two four-week treatments of allopurinol and benzbromarone separated by a four-week washout period. The serum uric acid level was reduced from 9.89 +/- 1.43 mg/dl to 5.52 +/- 0.83 mg/dl and from 9.53 +/- 1.48 to 4.05 +/- 0.87 mg/dl by allopurinol and benzbromarone, respectively. The efficacy of benzbromarone in lowering serum uric acid level was significantly superior to allopurinol (p=0.005). No patient reported clinical side effects during treatment with either drug. In conclusion, the authors have shown that benzbromarone is more effective than allopurinol in the reduction of serum uric acid levels in hyperuricemic patients with normal renal function.