After curative surgery for rectal cancer, the goal of an aggressive surveillance programme is the detection of local recurrence (LR) at an early and potentially curable stage 62 patients (mean age 66.2 years) operated on for rectal cancer were prospectively enrolled in a follow-up study including endorectal ultrasound (EUS), serial CEA levels, digital examination, colonoscopy and pelvic CT. A total of 192 sonographic scans were performed, with a mean of three (range 2-7) for each patient. LR occurred in 11 patients; in all cases this was suggested by EUS. In two patients (18%) other techniques had failed to detect recurrent disease, which was identified solely by EUS. These two were treated radically and the remainder received radiotherapy or other palliative management. Five patients are alive at, on average, 18 months after LR (range 4-26 months). These include both cases treated with salvage surgery and who remain disease free. EUS is a valuable tool in the detection of locally recurrent rectal cancer.