Cat fish oil extracts (Pangasius hypophthalmus) contains omega-3 and albumin which controlling the blood glucose levels. Diabetes mellitus is a metabolic disease characterized by hyperglycemia syndrome and impaired metabolism of carbohydrates, fats, and proteins. The purposes of this study were to evaluate the effect of cat fish oil extracts in oral glucose tolerance test and pancreas histology of male rats and to determine the most effective dose of cat fish oil extract in decreasing the blood glucose level. This research used a completely randomized design with 6 groups of 4 male rats each. All treatments were injected with alloxan monohydrate at a dose of 150 mg/kg intraperitoneally, excluding normal control treatment. Normal control administered with Na-CMC 0,5% 1 mL/200 gr BB, negative control with Na- CMC 0,5% 1 mL/200 gr BB, and positive control with glibenclamide 0,45 mg/kg BB. The other groups were administered a dose of the extract as much a 18,2 mg/kg BB, 36,4mg/kg BB, and 72,8 mg/kg BB. Extraction was conducted using wet rendering method. Observed parameters were the oral glucose tolerance test (OGTT) and histology of the pancreas. The results showed that the cat fish oil extracts possessed an effect on OGTT and histology of the pancreas. Cat fish oil extracts dose of 72,8 mg/kg BB was the most effective dose in lowering blood glucose OGTT and in repairing island of Langerhans which were necrotic and the amount of blood glucose was closed to normal.