ABSTRACT We aimed to verify whether age influences the biochemical profile of healthy lambs during the first four months of life by characterizing the dynamics of its parameters and verifying whether there are differences between the profiles of growing animals and the reference values established for adults. Blood samples of 34 ½ White Dorper × ½ Suffolk female lambs were collected at 30, 60, 90, and 120 days of age, and the serum concentrations of total proteins, total globulins, albumin, urea, creatinine, bilirubins (total, conjugated, and unconjugated), total cholesterol, triglycerides, glucose, gamma-glutamyltransferase, aspartate aminotransferase, and creatine kinase were determined. Descriptive statistics of these parameters were performed to compare them with the reference intervals used for adult sheep. Age influenced the dynamics of all the biochemical parameters between 30 and 120 days of age. Moreover, except for the total, conjugated and unconjugated bilirubins, total cholesterol, and aspartate aminotransferase means, the values of the lambs differed from the reference intervals established for adults. In conclusion, there is an influence of age on biochemical parameters in healthy female lambs in the first four months of life, and often the biochemical parameters of young animals differ from those of adults. Therefore, the interpretation of tests performed on growing animals should be made based on specific reference intervals for this age group.