The relationship between associated movements (AMs) and level of motor performance is not well understood. In this study we investigated whether children with developmental coordination disorder (DCD), with (n = 10) and without (n = 10) attention deficit hyperactivity disorder (ADHD), and a control group (n 10), differed in the severity of AMs. A total AM severity score was obtained for each child by rating their performance on AM tasks. Both groups with motor difficulties had significantly more severe AMs than the control group. A significant correlation was found between level of motor performance and total AM scores (r = -.62). Our results suggest that level of motor performance should be considered in future research attempting to understand individual differences in severity of AMs as a function of motor, learning, and behavioural disorders. (c) 2005 Elsevier B.V. All rights reserved.