Serum chemistry values were obtained from 64 adult San Joaquin kit foxes (Vulpes macrotis mutica) in western Kern County, California (USA). The goal of the study was to establish normal chemistry values for this endangered species. No significant differences were found for mean values of alanine aminotransferase (217.1 IU/l), alkaline phosphatase (44.2 IU/l), cholesterol (145.6 mg/dl), total protein (5.8 g/dl), creatinine (0.63 mg/dl), calcium (8.2 mg/dl), albumin (3.0 g/dl), glucose (129.2 mg/dl), amylase (196.8 IU/l), sodium (153.7 mEq/l) and phosphorus (5.42 mg/dl) between sexes or seasons. Significant differences were noted for aspartate aminotransferase, blood urea nitrogen and potassium between seasons. Possible disturbances in normal hepatic and renal functions were noted.