The hematology and blood chemistry of 10 captive adult Ara rubrogenys is described. 2. They showed 3,650,000 erythrocytes/mm3, a hematocrit of 49.9% and a blood hemoglobin content of 15.2 g/100 ml. 3. Leukocyte number was 10,000 cells/mm3, the differential counts being 42.2% heterophils, 0.8% eosinophils, 2.4% basophils, 49.9% lymphocytes and 4.5% monocytes. 4. The number of thrombocytes was 21,800 cells/mm3. 5. Plasma composition was (mg/100 ml): glucose 295; triglycerides 102; cholesterol 166; urea 5.8; uric acid 5; creatinine 0.3; bilirubin was not detected and total protein concentration was 3.2 g/100 ml. Enzymatic activities were (units/1): GOT 188; GPT 10 and alkaline phosphatase 315.