Peak-flow measurement increasingly seems to be very useful for routine monitoring of asthma in children. The purpose of this study was to evaluate the reliability and reproductibility of three different peak-flow meters: Miniwright, Vitalograph and Assess. This prospective study was conducted in 100 primary school children aged from 6 to 11 years. In each child, 9 measurements of expiratory peak-flow rate (EPF) were performed with these 3 peak flow meters in a random order. Reproductibility was assessed for each instrument by the greatest divergence observed between the 3 EPF values measured in the same session. Reliability was assessed by comparison between the values obtained with each instrument and theoretical EPF values calculated from a formula which included age, sex and size. Our study validated the reliability and reproductibility of the 3 peak flow meters studied. EPF values were more scattered and less reproductible with Assess, but the difference was not significant.