Anorectal manometry and suction biopsy were carried out on 47 children with constipation or soiling, or both. Patients were divided into two groups. Group 1 (37 patients): functional faecal retention, group 2 (10 patients): functional faecal soiling without retention. Ganglion cells or normal acetylcholinesterase staining, or both, was demonstrated in all cases. Normal inhibition of internal sphincter could be achieved by rectal distension in all except 2 children with severe constipation. Resting sphincteric pressures, pressure responses, and conscious rectal sensitivity thresholds were similar in groups 1 and 2, but were increased compared with controls. In group 1 alone, the critical volume increased parallel with conscious rectal sensitivity threshold. Since the complete relaxation of internal sphincter occurs before conscious rectal sensation arises in children with soiling without retention, this may be an important factor, at least in some of the soilers.