OBJECTIVE: To determine valuable radiologic criteria in diagnosis of pes cavus. METHOD: Thirty eight healthy subjects and twenty seven pes cavus cases were evaluated by radiologic measurements. We evaluated the criteria for longitudinal arch curve by measuring the calcaneal pitch, talocalcaneal angle, talometatarsal angle, metatarsal angle and navicular height I and II. RESULTS: By comparing the pes cavus with the control group, no significant differences in the talocalcaneal angle, metatarsal angle and navicular height I and II were found. Whereas we found a significant difference between the talometatarsal angle and calcaneal pitch. Talometatarsal angle is more sensitive and specific compared to the calcaneal pitch. CONCLUSION: In diagnosis of idiopathic pes cavus, talometa tarsal angle is more reliable in the diagnosis of pes cavus. The ultimate diagnostic value of talometatarsal angle in pes cavus is 6degrees.