The purpose of this study was 1) to establish the interrater reliability of classifying foot type by visual appraisal and 2) to determine any relationship between foot type and subsequent knee pain or ankle sprains. Seventy-seven athletes were evaluated by three trained physical therapists to determine interrater reliability of a visual appraisal to identify foot type. Feet were classified according to operational definitions, and specific criteria had to be met for the foot to be classified as supinated, pronated, or neutral. Questionnaires concerning knee pain were completed at the beginning of the season, and incidence of ankle sprain was followed throughout the football and cross country seasons for 55 athletes. The Kappa value for interrater reliability for visually assessing foot type was .72. There was a significant relationship between foot type and knee pain (X2 = 4.45, N = 55, df = 2, p < .05). There was no relationship between foot type and incidence of ankle sprain. These results indicate that 1) physical therapists trained in the procedure can reliably use visual appraisal to classify foot type, and 2) athletes with excessively pronated or supinated foot types may be more susceptible to knee pain than athletes with neutral foot types. J Orthop Sports Phys Ther 1991;14(2):70-74.