The aim of this study was to evaluate the differences among strength, speed and endurance in 11-13 age girls and boys and development of these biomotor abilities according to age. Totally 305 children have joined this study. Height, weight, standing broad jump, 20 m. Sprint run, 15 s crunch test, 10 s. Push-up test, 20m. Shuttle Run tests (Eurofit Tests batteries) have been measured. The differences obtained from the test results between girls and boys who joined the study have been analysed. In both groups at age of 11 and 13 significant differences were found between all parameters (p<0,05). Between weight and standing broad jump, 15 s crunch test significant differences were found on children at age of 12.