Abstract: Gelatin is a polymer of amino acids that are found in collagen on skin tissue and animal bones. The skin of lencam (lethrinus lenjan) is one of gelatin source. Gelatin can be obtained from collagen by acid treatment (type A) or with base treatment (type B). Gelatin from fish skin generally obtained by acid treatment, because the collagen tissue of fish skin is softer than tissue on bones. Gelatin from lencam skin is extracted by phosphoric acid in concentrate 1%, 2%, and 3%. For the higher gel strength 14,04 N, viscosity 6,8% and the higher amino acids is Glycine 24,48%. Overall, there are 15 amino acids profile that contain in fish skin gelatin. Amino acids composition determined by UPLC (Ultra Performance Liquid Chromatography).