Background: Clinical investigations of plaque removal efficacy of power toothbrushes in children are limited. Aim: To compare plaque removal of a power versus manual toothbrush in a paediatric population. Design: This was a randomised, replicate-use, single-brushing, examiner-blinded, two-treatment, four-period crossover clinical trial in children 8–11 years of age. Subjects were randomly assigned to a treatment sequence involving an oscillating–rotating power toothbrush and a manual toothbrush control. Subjects brushed under supervision with a NaF dentifrice. Plaque was assessed pre- (baseline) and post-brushing using the Turesky Modification of the Quigley-Hein Plaque Index by two examiners. Plaque scores were averaged for mixed and permanent dentition on a per-subject basis and analysed using a mixed-model ancova for a crossover design. Results: Forty-one subjects (mean 9.0 years) were randomised and completed the trial. Both the power brush and manual brush provided statistically significant mean plaque reductions versus baseline in all analyses (P < 0.001). For both examiners, plaque removal was significantly (P < 0.001) larger for the power brush in permanent and mixed dentitions. The interexaminer correlations for the permanent dentition were strong (ICC = 0.68–0.88) for pre-brushing plaque across all periods. Conclusions: An oscillating–rotating power toothbrush provided superior plaque reduction versus a manual toothbrush in children.