Electronic diary assessment of pain and disability has become increasingly popular in adult chronic pain research but use of this methodology with children has received limited attention. The aim of this study was to compare two formats of a prospective daily diary (handheld computer=e-diary; paper diary=p-diary) on children's compliance, accuracy, and acceptability ratings. Sixty children, ages 8-16 (M=12.3) with headaches or juvenile idiopathic arthritis, were randomized to receive either e-diaries administered via home visits (n=30) or p-diaries (n=30) handed out during clinic visits for return by mail. Results demonstrated significant mean differences in diary entries completed between groups, with children with e-diaries completing more days (M=6.6) compared to children with p-diaries (M=3.8), P<0.001. Diaries returned by children in the p-diary group contained significantly more errors and omissions compared to diaries returned by children in the e-diary group (which contained none), P<0.001. Children rated both diary formats as highly acceptable and easy to use. A significant gender x diary format interaction (P<0.01) was found for compliance where boys demonstrated greater compliance with the e-diary format. Findings demonstrated that the e-diary was feasible to use with children and showed significantly greater compliance and accuracy in diary recording compared to traditional paper diaries in a population of children with recurrent pain.