Hematologic and serum biochemical values were determined for 26 (16 males and 10 females) clinically healthy captive fossas (Cryptoprocta ferox) living at Zoo Duisburg, Germany. The animals were net-restrained and anesthetized with ketamine and medetomidine for a general examination. A total of 11 animals were classified as subadult (1–3 yr of age) and 15 as adult (aged between 4 and 13 yr). The results include reference intervals and analysis of sex and age differences. Levels of inorganic phosphorus, alkaline phosphatase, glutamate dehydrogenase, creatine kinase, lactate dehydrogenase, and calcium were significantly higher in the subadult group. The white blood cell count and red blood cell count were significantly lower in the adult group than among the subadult group.