This study was undertaken to determine simultaneously the effects of alfuzosin on urethral and blood pressures in the same conscious male rat. Alfuzosin (i.v., 3, 10 and 30 micrograms/kg) dose-dependently decreased urethral pressure without affecting mean arterial blood pressure. At the higher dose, blood pressure was only slightly and transiently decreased while a marked decrease (-40%) in urethral pressure was observed. Therefore, this experimental model is suitable to assess uroselectivity.