The case of a 14-year-old girl is presented who was born with sacral agenesis and severe, chronic constipation not responding to laxative treatment. Biofeedback was employed in the treatment of the constipation and soiling. After six treatment sessions over four months, the constipation and soiling ceased and there was no relapse during follow-up of 12 months. Although this child had an absence of S3-S5 and the coccyx, with possible innervation abnormalities, this case illustrates that biofeedback training might be a useful adjunct to existing therapies.