Brazil. Design the protocol, final approval of the version to be published. ABSTRACT PURPOSE:To evaluate the effect of diabetes mellitus and of sildenafil citrate on female urethral function. METHODS:Twenty nine female rats were divided into four groups: G1 -(n=9), normal rats; G2 -(n=6), normal rats treated with sildenafil citrate; G3 -(n=9) rats with alloxan-induced diabetes; G4 -(n=5) rats with alloxan-induced diabetes treated with sildenafil citrate. Under anesthesia, urodynamic evaluation was performed by cystometry and urethral pressure simultaneously. RESULTS:A significant increase in urethral pressure was observed during micturition. CONCLUSION:Sildenafil citrate can partially reduced urethral pressure in diabetic female rats.