Sutiyono, Sutopo, Ondho YS, Setiatin ET, Samsudewa D, Suryawijaya A, Lestari DA, Kurnianto E. 2018. Genetic diversity ofOngole Grade Cattle of Rembang District, Central Java, Indonesia, based on blood protein polymorphism. Biodiversitas 19: 1429-1433. The objective of this study was to identify genetic diversity in Ongole Grade cattle of Rembang District, Central Java, Indonesia,based on blood-protein polymorphism. A total of 34 blood samples were collected from unrelated Ongole Grade cattle and the bloodplasm was used to identify the blood proteins. Blood protein analysis was performed using Sodium Dodecyl Sulfate-Polyacrilamide GelElectrophoresis (SDS-PAGE). Observed bands were used to perform allele interpretation of four loci, namely Albumin (Alb), Postalbumin(Po-Alb), Ceruloplasmin (Cp) and Amylase-1 (Am-1). Results showed the presence of polymorphism in all of the four bloodproteinloci, average heterozigosity value (H) being 0.506 and almost all of the blood-protein loci studied showed deviation from Hardy-Weimberg Equilibrium (HWE). In conclusion, the study indicated that population of Ongole Grade cattle in Rembang, Indonesia hashigh genetic diversity.