SummaryTo distinguish age‐related changes in hematology and clinical chemistry values from those resulting from disease, hematology, and clinical chemistry values of healthy, age‐matched Beagle dogs 3 to 14 years of age were analyzed. Serum potassium, total protein and globulin concentration, and lactic dehydrogenase activity increased with age, while urea nitrogen, creatinine and albumin concentration, and gamma‐glutamyl transferase activity decreased. The 12‐year‐old group had some distinct differences from the other age groups: glucose concentration was lower, alanine aminotransferase and aspartate aminotransferase activity and triglyceride concentration were higher. No significant age‐related differences were found in the hematology parameters analyzed. This report extends the documented, age‐related changes in normal Beagle dogs to 14 years of age.The age‐related changes in organ‐specific serum chemistries such as urea nitrogen and creatinine (kidney), and alanine aminotransferase (liver) noted here suggest that 12 years may be a pivotal age for determining longevity