Background: Portunus pelagicus crab species meat is generally taken, and their shells that is thrown away becoming untapped waste. Their shells contain so many useful minerals such as calcium carbonate which can be processed into hydroxyapatite (HA). HA has been extensively used in the medical field for bone grafting, to repair damaged in bone structures. Purpose: To determine the biocompatibility of hydroxyapatite from Portunus pelagicus crab’s shells extract after sterilized using UV on human gingival fibroblast cell. Methods: This research is an experimental laboratory research using post-test only control group design. The shells were first heated using furnace. Once hydroxyapatite was obtained, it was sterilized using ultraviolet (UV) with certain concentration (25 ppm, 50 ppm, and 100 ppm) to kill the microorganisms. MTT assay was done to test the biocompatibility of the sterilized hydroxyapatite on human gingival fibroblast cell. Results: The highest viability of fibroblast cells was the group with 50 ppm UV (98.10%), followed by 100 ppm UV (97.93%), and 25 ppm (93.28%). Conclusion: Hydroxyapatite from Portunus pelagicus crab’s shells extract sterilized using UV is biocompatible towards human gingival fibroblast cell.