Serum biochemical parameters were studied in 42 healthy wild-caught adult tamarins (S. mystax), males and females, to determine the normal values. Blood samples were drawn repeatedly, and the serum was tested for aspartate aminotranferase, alanine aminotransferase, isocitric dehydrogenase, serum glucose, serum urea, triglyceride, cholesterol, albumin, and tolat protein. The results indicated that serum chemistry values were similar to those reported as normal for both humans and other Callitrichidae species. The study of serum biochemical parameters in tamarins with experimental hepatitis A indicated that serum enzyme activities alone reflected the hepatic damage, while other biochemical parameters were of no real clinical importance. The experimental results showed the levels of serum urea to be indicative of the pathological involvement of the kidneys in experimental hepatitis A in some cases.