PurposeThe Unstable Platform for Balance Analysis (UP-balance) has been used in several studies to evaluate different situations of balance and constraints. However, the reliability of its measurements has not been analysed yet. Therefore, the present study investigated the reliability of the measures provided by UP-balance in young adults in bipedal posturę with and without vision.MethodsFor such analysis, 30 young adults, male and female (mean age: 22.9 years; <i>SD</i> = 3.8 years), performed 3 attempts of the task which consisted in maintaining balance on an UP-balance on a bipedal base for 20 seconds, with and without visual information, with perturbations in the medial-lateral and anterior-posterior directions.ResultsThe UP-balance variables presented high inter-trial reliability (ICC > 0.76; <i>p</i> < 0.05), except for balance time in the anterior-posterior direction and non-vision condition, which exhibited moderate inter-trial reliability (ICC = 0.73; <i>p</i> < 0.05).ConclusionsUP-balance seemed to be a reliable instrument for the analysis of balance in situations of instability on a base support.