Background Reliability is an integral component of clinical assessment and necessary for establishing baseline data, monitoring treatment outcomes and providing robust research findings. In the podiatric literature traditional measures of foot assessment have been shown to be largely unreliable. The Foot Posture Index (FPI-6) is a clinical tool used in the assessment of foot and to date, there is limited research published which evaluates the reliability of this tool in children and adolescents. Method Thirty participants aged 5 - 16 years were recruited for the research. Two raters independently recorded the FPI-6 score for each participant. Results Almost perfect agreement between the two raters was identified following weighted kappa analysis (Kw = 0.86). Conclusion The FPI-6 is a quick, simple and reliable clinical tool which has demonstrated excellent inter-rater reliability when used in the assessment of the paediatric foot.