OBJECTIVE Sacral neuromodulation (SNM) has been a successful treatment in urinary voiding disorders for years. A concomitant effect on bowel function was observed leading to the treatment of faecal incontinence with SNM. In this study we describe the effect of SNM on bowel frequency and (segmental) colonic transit time. METHODS Fourteen patients with faecal incontinence who qualified for permanent SNM underwent a colon transit study before and one month after permanent implant. Patients completed a three-week bowel habits diary before and during stimulation. RESULTS Median incontinence episodes and days per week before SNM were, 8.7 and 4.2, respectively, and both decreased significantly to 0.67 (P = 0001) and 0.5 (P = 0001) during trial screening and to 0.33 (P = 0001) and 0.33 (P = 0001) after permanent implant. The median number of bowel movements per week decreased from 14.7 (6.7-41.7) to 10.0 (3.7-22.7)(P = 0005) during trial screening and to 10.0 (6.0-24.3)(P = 0008) during permanent stimulation. Resting and squeeze pressures did not change significantly during stimulation. Segmental colonic transit time before and during stimulation for right colon, left colon and recto sigmoid were, respectively, 6 (0-25) vs 5 (0-16) hours, 2 (0-29) vs 4 (0-45) hours and 7 (28) vs 8 (0-23) hours. No significant changes were found in both segmental and total colonic transit time; 17 (1-65) vs 25 (0-67) hours. CONCLUSIONS SNM in patients with fecal incontinence led to a significant decrease of bowel movements however (segmental) colonic transit time was not influenced.