In this study, the effects of phase change material (PCM) cooling for a tracking-integrated concentrating photovoltaic-thermal (CPV-T) system are investigated experimentally. By designing a small scale CPV-T system with immersed encapsulated PCM spheres, the on-site experimental measurements were performed. The relationship of the electrical, thermal, and overall efficiencies with the solar irradiance is explored. The results are also compared to the existing CPV-T system with water cooling. Results show that compared with the CPV-T system with water cooling, the average increases of the electrical, thermal, and overall efficiencies for the CPV-T system with PCM cooling are more than 10%, 5%, and 15%, respectively. The comparison results demonstrate that using the PCM cooling is an effective way to improve the performance of a CPV-T system.