This study evaluated the effects of platelet-rich plasma (PRP) on resorption and adipocyte survival in autologous fat-graft of rats prepared with isogenous PRP. Fat grafts prepared without PRP (control group) became united to the tissue adjacent to the implantation site and were significantly resorbed from 30 days. On the other hand, fat grafts prepared with PRP (PRP group) demonstrated little resorption from 30 to 120 days and appeared pink, had a soft, supple feel, and were easily compressible. Histologic sections of grafts in the control and PRP groups at 10 days exhibited similar consolidation of the grafted tissue, which contained morphologically normal adipocytes with different degrees of granulation and capillary formation. From 20 days normal adipocytes were obviously decreased in the control group, while the PRP group demonstrated increased granulation tissue and capillary formation and good maintenance of normal adipocytes for at least 120 days.