Objective: This study evaluated the potential effects of short-term treatment with lisdexamfetamine dimesylate (LDX) on both subjective and objective sleep characteristics in children aged 6 to 12 years (n = 24) with ADHD. Method: Polysomnography (PSG) and actigraph measures as well as assessments of subjective sleep parameters were examined in children before and after treatment with either LDX or placebo in a randomized, double-blind, single-center, parallel-group study. Results: There was no statistically significant increase in the primary endpoint of latency to persistent sleep (LPS) for the LDX-treated group compared to the placebo group. Secondary PSG or actigraph results generally supported primary endpoint results. Subjective sleep measure results indicated the possibility that responses are influenced by sleep hygiene counseling before and throughout the study. Conclusions: In this pilot sleep study in children with ADHD, LDX did not appear to contribute to any sleep disturbances as measured by both objective and subjective sleep parameters. The sample used in this study was small, and the multifarious nature of findings in this study warranted that the study conclusions be interpreted cautiously and that further study is required focusing on the influence of LDX on sleep in larger samples of ADHD children. (Contains 5 figures and 3 tables.)