The aim of the present study was to investigate the effect of oral diazepam on anal incontinence after low anterior resection for rectal cancer. Five patients with persistent incontinence after low anterior resection for rectal cancer (median level of anastomosis was 4.0 cm from the anal verge) were treated with oral diazepam (2 mg/day) 9-90 months after surgery. Grade and frequency of anal incontinence, the need for a protective pad and changes of lifestyle were recorded to the Cleveland Clinic's continence grading scale; anorectal manometry was performed before and after 3 months of treatment. All patients improved on treatment although occasional minor soiling persisted in two patients. Continence score improved from 14 (median, range 9-16) to 0 (range 0-12) after taking diazepam. Improvement occurred within a week after administration of diazepam. Although the patients improved symptomatically, anorectal manometry failed to demonstrate any significant changes. In conclusion, oral administration of diazepam may be worthwhile in the attempt to improve anal continence after low anterior resection.