Abstract: Gelatin is a protein resulted from partial collagen hydrolysis made from animal’s skin or bones. Mahi-mahi or lemadang fish is one of the large pellagic fish commercialized as fillet while its bone and skin was mostly unused and thus suitable to produce gelatin. Objective of this study was to found out the best physicochemical properties of gelatin made from mahi-mahi skin after curing for 6, 7 and 8 hours using tartaric acid. Best result shown in 8 hours curing with rendemen 14,04%, gel strength 14,75 N, viscosity 6,52 cP; protein content 86,18%; fat content 0,46%; water content 8,18%; pH 4.87 and glicyn amino acid content 23,09% and prolin 13,22 as the main amino acid structure in gelatin.