A prospective study of pes planus by using calcaneal pitch and calcaneal spur was carried out in 82 patients with plantar heel pain and in 400 normal subjects. The mean normal calcaneal pitch was 20.54 degrees. The mean calcaneal pitch in patients with plantar heel pain was 15.99 degrees, which was significantly lower than in normal subjects. The incidence of calcaneal spur in normal subjects and in patients with plantar heel pain was 15.5% percent (62 of 400) and 65.9% (54 of 82), respectively. Again, this was a highly significant difference. Excessive weight gain, aging, and gender may be important factors effecting the lowering of the pitch and the increasing of spur formation. These factors could lead to the development of plantar heel pain.