Little is known about chronic constipation in infants, toddlers, and preschool children and longterm outcome after treatment. The symptoms of 174 children < or = 4 years of age, who were evaluated for chronic constipation, are reported in this study together with the long-term outcome in 90 of them. Initial symptoms were infrequent bowel movements in 58%, painful bowel movements in 77% often with screaming, and severe stool withholding manoeuvres in 97%. The treatment of chronic idiopathic constipation consisted of education, faecal disimpaction, prevention of future impaction, and promotion of regular bowel habits with dietary fibre and milk of magnesia, and finally toilet training of the preschool child. Longterm outcome could be evaluated in 90 patients (52%) (mean (SD) 6.9 (2.7)) years after initial evaluation. Fifty seven children (63%) had recovered, defined as no soiling with > or = 3 bowel movements per week, while not receiving treatment. The recovery rate of children < or = 2 years of age was significantly higher than in children > 2 to 4 years of age. Thirty three children (37%) had not recovered. Constipation recurred as soon as laxatives were discontinued in 31 (94%) of them. Laxatives were still used by 33% of the children who had not recovered, 39% had < 3 bowel movements per week, 48% had faecal soiling, 45% had stool withholding, 27% complained of abdominal pain, 73% passed large stools, and 45% still on occasions clogged the toilet with their large stools. Symptoms of chronic constipation persisted in one third of our patients, 3-12 years after initial evaluation and treatment. Children who had not recovered deserve continued follow up, to reinforce and adjust treatment and to prevent faecal soiling.