Introduction: Flat foot is usually an indication of a very low foot arch. The development of foot arch is brisk between ages 2 and 6 but becomes structurally perfected around age 12 or 13. This study assessed Flat foot in school children aged 6-12 years in Asaba metropolis, Delta State, Nigeria. 

Materials and Methods: This quantitative and descriptive cross-sectional survey employed the use of 350 children (175males and 175females) who were randomly selected. Foot prints were obtained by the ink and plain paper method. Measurements of the parameters for the index were made on the prints and Chippaux-Smirak index (CSI) was thereafter calculated according to a previously recommended method. Paired samples T-Test was used for determining differences between the right and left feet while Chi-square was used to determine gender differences.

Results: Results showed that the mean CSI for the right and left foot were 41.90±0.69 and 42.29±0.69 respectively. There was no statistically significant difference between flat foot of the right side and that of the left (p>0.05). Also, there was no statistically significant gender difference in flat foot on both foot sides. Normal arch was most prevalent with 48.6%, while flat foot (36.4%) was more prevalent than high arch (15.0%). Flat foot, high and normal arch types showed no sexual dimorphism in the studied population. 

Conclusion: This study has shown that flat foot is more common in females than in males among children between 6 and 12years in Asaba, Delta State, Nigeria. Thus, further studies on the effects of nutrition on flat foot should be conducted in the studied population.