BACKGROUND : There is evidence that children with high cardiorespiratory fitness and normal body mass index (BMI) have less risk of non-communicable diseases (NCDs), however limited research was undertaken in Omani children. Therefore the aims of the present study were to describe body composition and physical fitness of a large cohort of Omani school children of both genders, and to investigate the effects of weight status on physical fitness. METHODS : Three hundred and fourteen Omani school children aged 9 to 10 years old took part in anthropometric assessments, body composition and fitness tests, including handgrip strength, the basketball chest pass, broad jump, 20-m sprint, four 10-m shuttle agility, 30-s sit-up, and multistage fitness test (MSFT). RESULTS : Obese boys and girls performed worse than normal-weight children in sprint, agility and endurance. In addition, fitness measures in the overweight group and underweight groups were not significantly different from other groups, except a better handgrip strength and poorer MSFT in overweight compared to normal weight girls, and poorer agility performance in underweight girls compared to the three other groups. CONCLUSIONS : Most fitness measures are lower in obese Omani children, which suggests that they will be more at risk of developing NCDs later in life.