Hydroxyapatite Caio (P04) e (OH) 2 is an alloplast material that is used to increase bone regeneration. It can be synthesis by processing natural materials such as fish bones. The purpose of this study was to synthesize hydroxyapatite from natural resources skipjack tuna (Katsuwonus pelamis) bones with precipitation method. Then, characterize hydroxyapatite morfology with FESEM and its biocompatibility using the preosteoblast MC3T3-E1 cell line. Skipjack tuna bone was synthesized into hydroxyapatite through precipitation method. The morphology of hydroxyapatite sample was revealed with field-emission scanning microscope FESEM. While the constituent elements were analyzed using SEM EDAX. Biocompatibility of hydroxyapatite was tested using preosteoblast cell culture. Cells were treated with different hydroxyapatite concentration 200 μglml, 100 μglml and 5 &# x03BC; g/ml. After incubation with C02 5% at 37 C for 24h, 48h and 72h the cultore was tested for viability using MTT Cell Viability Assay Kit. Results were reported as optical density. The study showed that skipjack tuna bone produced grain-shaped particles with almost uniform sizes. The surface material appears to be agglomerates and form pores in between. Weight percentages Ca/P ratio for hydroxyapatite from skipjack tuna bones is 1.94. MTT assay showed cell viability after 3 days. These results suggest that skipjack tuna bone hydroxyapatite is has potential as bone engineering biomaterial