The authors report the data obtained in a bone scan study conducted in 15 patients with cementless total hip arthroplasty. The study was conducted a minimum of 6 months and a maximum of 46 months postsurgery. Contrary to what occurs for cemented prostheses, we used bone scan not as a diagnostic aid for complications, but in order to evaluate the osteogenetic response of the bone to a cementless prosthetic implant. Zonal bone scan high uptake revealed specific areas of overloading, or, when localized in the para-articular region, they anticipated the presence of ossifications before they became visible radiographically. Bone scan was also useful in monitoring the incorporation and remodelling phases of the auto and/or homoplastic bone grafts used.