The incidence of urethral instability after total hysterectomy for cervical cancer was analyzed in 154 patients allocated to one of two groups according to the extent of vaginal resection. Evaluations were conducted during urodynamic exploration prior to and 1 year after surgery. Persistent instability of urethra at 1 year follow-up was noted only in the group in which the resection had involved 2/3rds of the vagina, 18% of these patients being assessed as possessing urethral instability. Variations in maximum pressure greater than 30 cm H2O resulted in major clinical and urinary disorders.