Hematologic and serum chemistry values were determined for 25 free-ranging Florida panther (Puma concolor couguar) neonates from southern Florida sampled from January 2001 to April 2007. The kittens were ≤25 days old, belonging to 12 litters, from 11 different dams. Forty-one blood samples also were collected from 32 free-ranging adult panthers (3–10 yr-old) from southern Florida from November 2000 to February 2007. Male kittens had higher hemoglobin (Hb), hematocrit (HCT), and red blood cell (RBC) counts than did female kittens. Neonates had higher mean serum values of total bilirubin, alkaline phosphatase, cholesterol, calcium, phosphorus, triglycerides, and magnesium than adult panthers but lower mean values of urea nitrogen, creatinine, total protein, albumin, alanine aminotransferase, aspartate aminotransferase, sodium, chloride, creatine kinase, amylase, and total globulin. Neonates also had higher mean values of mean cell volume, mean cell hemoglobin, mean cell hemoglobin concentration, platelets, and the number of lymphocytes and monocytes but lower Hb, HCT, white blood cell count, RBC count, and neutrophils than adult panthers. No other significant differences in serum chemistry or hematology were noted between neonates and adults.