Abstract. Atma Y, Lioe HN, Prangdimurti E, Seftiono H, Tahufik M, Fitriani D, Mustopa AZ. 2018. The hydroxyproline content on fish bone gelatin from Indonesian Pangasius catfish by enzymatic hydrolysis for producing of bioactive peptide. Biofarmasi J Nat Prod Biochem 16: 64-68. Gelatins has been widely used in food, medicines, cosmetics, photography industries. In the food industry, gelatin used as food additives and functional foods. The applications of gelatin as a functional food due to their bioactivity in a form of peptides. Bioactive peptides from gelatin are mostly obtained through enzymatic hydrolysis processes. This study was conducted to measure the hydroxyproline content of gelatin bone of Indonesian Pangasius catfish (Pangasius sutchi) before and after enzymatic hydrolysis. The hydroxyproline is one of the dominant amino acids in gelatin. Gelatin hydrolysis was carried out using a flavourzyme at concentration of 6% and the incubation series of 0, 4, 6 and 8 hours. The standard concentration of hydroxyproline was used in range of 0-1 μg. The results showed that the linear curve of the hydroxyproline standard solution was y=0.0554x+0.0406, with the coefficient of determination (R²) = 0.9435. The incubation time of enzymatic hydrolysis (6% enzyme concentration) affected the hydroxyproline content. The hydroxyproline from fish bone gelatin was 18.91±2.87 mg/mL, 63.81±1.28 mg/mL, 46.21±1.28 mg/mL and 37.64 ± 0.64 mg/mL respectively during 0, 4, 6 dan 8 h incubation time. This hydroxyproline content was significantly different at 95% confidence level from each treatment time.