In this paper, four pairs of insoles with different comfort characteristics were used to investigate the relationship between the pressure distribution under the foot and running shoe comfort. Fourteen male subjects were tested in four insole conditions by walking and running on a treadmill. The pressure at the plantar surface of the foot was measured by using an EMED pressure-measuring insole. For walking there were significantly higher pressures and forces in the midfoot area and significantly lower pressures in the medial forefoot and hallux area by wearing the most comfortable insole compared with wearing the least comfortable insole. The shift of the pressure from forefoot to midfoot for the most comfortable insole provided an even distribution of the pressure at the plantar surface of the foot. The results also demonstrated that the path of centre of force at the plantar surface of the foot moved to the lateral aspect of the foot for the most comfortable insole. For running, only the pressure in the medial forefoot area was found significantly lower for the most comfortable insole than for the least comfortable insole. The results of this study indicated that the pressure distribution between the plantar surface of the foot and the shoe could detect the change of shoe comfort. Thus it is a suggestion that pressure measurement may be related to understand factors important for shoe comfort. Comfort of sport shoes is important for the appropriate execution of sport activities. Additionally, comfort may influence fatigue and possibly the development of injuries. The quantification of comfort of sport shoes and the understanding of mechanical and/or biological functions related to it may be enhanced with the use of pressure measurements between the plantar surface of the foot and the shoe sole.