Purpose: The heel fat pad has a unique structure that is important for its shock absorbing function. Loss of elasticity and change in the thickness of the heel pad have been suggested as cause of heel pain. The present study shows the relationship between the thickness of heel fat pad and age, sex, obesity and plantar heel pain. Materials and Methods: A study of heel pad thickness using plain lateral radiographs, unloaded by body weight, was carried out on 66 patients with plantar heel pain and 326 normal subjects. The population was divided into two or three groups according to their age, sex, body mass index, and the presence of symptom. We evaluated the differences in heel pad thickness between groups, and the relationship between BMI and Sex and Age was also determined, using statistically analytic method by SPSS version 10.1 program. Results: Heel pad thickness was greater in the subject over 40 years old (p<0.001), and in the overweight (p<0.001), and male heel pad was thicker than female (p<0.001). But there was no statistically significant difference for heel pad thickness between normal subject and plantar heel pain group. Conclusion: In this study, we found that there is a relationship between heel pad thickness and age, sex, and obesity. But we could not show that the difference of heel pad thickness is contributing factor to plantar heel pain. Although it could not be proved statistically, we believe that a change of heel pad thickness play a role in the development of heel pain. So we are planning to assess a relationship of heel pad elasticity and thickness and plantar heel pain again with prospective study method on the basis of the results of this study.