Hematological and serum biochemical values were determined in a wild population of the mountain brushtail possum (Trichosurus caninus) at Cambarville, central Victoria, southeastern Australia. Animals were sampled during two-week trapping periods in June, September, and December 1992, and April 1993. Values for hemoglobin, red cell count and hematocrit were significantly higher in males than females. Total protein and mean corpuscular volume (MCV) were significantly higher in female T. caninus. Significant seasonal variations were detected for total bilirubin, alkaline phosphatase, total protein, albumin, urea, absolute eosinophils, MCV, sodium, potassium, and phosphate.