PURPOSE: The purpose of the current in vitro study was to evaluate the transfer of metal to both alumina and cobalt-chrome (Co-Cr) heads that were scraped by a titanium alloy surface under different load conditions. MATERIALS AND METHODS: Alumina and Co-Cr heads were scraped by an acetabular metal shell under various loads using a creep tester. Microstructural changes in the scraped area were visualized with a scanning electron microscope and chemical element changes were assessed using an energy dispersive X-ray spectrometry. Changes in the roughness of the scraped surface were evaluated by a three-dimensional surface profiling system. RESULTS: Metal transfer to alumina and Co-Cr heads began to be detectable at a 10~15 kg load, which could be exerted by one-handed force. At loads of 30, 50 kg, fissures occurred on the head surfaces in addition to metal transfer. CONCLUSION: This study reveals that metallic debris was transferred from the titanium alloy acetabular shell to both alumina and Co-Cr heads by minor scraping. When the contact force increased, scratching of the head surface occurred in addition to the transfer of metal. The results of this study suggest that the greatest possible effort should be made to protect femoral heads, regardless of material, from contact with metallic surfaces during total hip arthroplasty.