The combination of prostate specific antigen (PSA) and transrectal ultrasonography was used to detect recurrent cancer in the prostatic fossa after radical prostatectomy. A total of 43 patients with persistently elevated PSA levels and negative bone scintigraphy following radical prostatectomy underwent digital rectal examination and transrectal ultrasonography. Ultrasound findings were considered suspicious if the scan showed any unusual hypoechoic tissue adjacent to the bladder neck, retro-trigone or peri-anastomotic site. Of 22 patients (51%) with biopsy proved cancer 21 (95%) had positive transrectal ultrasonography, while digital rectal examination was able to detect cancer in only 10 (45%). Among transrectal ultrasonography detected recurrences 15 (68%) were detected at the initial biopsy and 7 (32%) at repeat biopsies. Our study shows that the combination of PSA and transrectal ultrasonography provides a more effective method than digital rectal examination and PSA to detect biopsy proved cancer following radical prostatectomy.