A prospective, randomised double-blind trial of suprapubic (SPC) versus transurethral (TUC) catheterisation was undertaken in fifty consecutive male patients of median age 66 (range 32-81) years undergoing pelvic colorectal surgery. Twenty-four patients were randomised to SPC. Catheter removal times were comparable between the two groups: SPC = mean 7.2 (3-14) days; TUC = man 7.5 (2-13) days; P > 0.5. Acute urinary retention was recorded in 5 patients with SPC and 6 in the TUC group. Chronic retention with overflow was recorded in one TUC patient. Frequent voiding after catheter removal occurred in two SPC, and in eleven TUC patients (P < 0.05). Re-catheterization was required in two SPC, and seven TUC patients. One culture positive urinary tract infection occurred in the SPC, and three in the TUC groups. It is concluded that suprapubic catheterisation allows comparable controlled return of normal voiding with fewer bladder and urethral symptoms when compared with transurethral catheterisation.