The aim of the present study was to analyse the daily variation of balance in two groups of female adolescents: elite athletes (n=20, aged 13.2 ± 0.5 years) and untrained students (n=20, aged 12.9 ± 0.6 years). Participants underwent two testing sessions over two days at two different times each day. Morningness-Eveningness self-assessment questionnaire was administered to assess the chronotype of the participants and oral temperature was measured too. Significant group differences were found in the overall balance tests (p<0.01). Athlete group showed no significant differences in balance tests with respect to the time-of-day. Untrained adolescents attained better results in the morning in the dynamic balance tests (p<0.01). No correlations were found between chronotype, oral temperature variations and balance tests scores. The main outcome of the study was that elite athletes did not show time-of-day effects on balance, whereas the untrained adolescents achieved better results in the morning.