AbstractObjectivesTo determine the gross motor skills of school-aged children after the Fontan procedure and compare the locomotor and object control skills with normative data.Study designThis study followed a cross-sectional design.SettingThis study was based on hospital outpatient visit, with accelerometry conducted at home.PatientsThis study included 55 patients, including 22 girls in the age group of 6–10 years, 5.1 years after Fontan.Main outcome measuresTest of Gross Motor Development – Version 2, daily activity by accelerometer, medical history review, child and parent perceptions of activity.ResultsBeing involved in active team sports increased locomotor percentile score by 10.3 points (CI: 4.4, 16.1). Preference for weekend outdoor activities (6.9, CI: 2.0, 11.8), performing at least 30 minutes of moderate-to-vigorous physical activity daily (24.5, CI: 7.3, 41.8), and reporting that parents seldom criticise the child's physical activity (21.8, CI: 8.9, 34.8) were also associated with higher locomotor percentile scores (p < 0.01). Object control percentile scores were higher (p < 0.03) with involvement in formal instruction (5.9, CI: 1.1, 10.6) and being restricted to “activities within comfortable limits” (27.6, CI: 7.7, 47.5). Older chronological age (r = 0.28), a more complicated medical history (r = 0.36), and older age at Fontan (r = 0.28) were associated with greater skill delay (p < 0.04).ConclusionsChildren after Fontan attain basic motor skills at a later age than their peers, and deficits continue for more complex skills as age increases, suggesting a need for longitudinal monitoring of gross motor skill development through the elementary school years. Future research might investigate whether a gross motor skill rehabilitation programme can provide these children with the motor skills needed to successfully participate in a physically active lifestyle with peers.