In a review of 538 children with functional constipation, we analyzed ages of presentation and onset, symptom duration, and behavioral/developmental problems. We divided the subjects into quartiles (Q1-Q4) based on age of onset. Median onset age was 2.3 years. The oldest group had the shortest symptom duration before referral at 1.8 ± 1.8 years (compared with Q3 to Q1, P = 0.039, P = 0.001, P < 0.001, respectively). Of the Q4 subjects, 22% had a behavioral/developmental problem (P < 0.001 compared with Q1-Q3). We conclude that most children develop functional constipation as infants and toddlers, but those with later onset are more likely to have behavioral/developmental issues and see a specialist sooner.