The serum levels of some pancreatic enzymes have been reported to be affected by age and gender. Currently, serum total amylase, pancreatic isoamylase (P-amylase) , lipase , trypsin (ogen) , pancreatic phospholipase A(2) (PLA(2)) , and elastase I are utilized in diagnosing pancreatic diseases. We here compared age and gender-related alterations of these six pancreatic enzymes in healthy subjects to delineate different properties among the enzymes. Subjects were 155 males and 172 females between ages 20 and 79 years who were apparently healthy, and were stratified by age and sex. PLA(2) and elastase I were assayed by RIA, trypsin (ogen) by EIA and others by activity. The pancreatic enzymes, except PLA(2), were significantly elevated with age, although they declined in males in the 260 age group. There were significant sex differences in total amylase and P-amylase. Total amylase was significantly higher in females than in males in the 260 age group, P-amylase in the 40-49 age group. Age should be considered in the valuation of serum enzymes except PLA(2), sex difference should be considered in the valuation of amylase (total and P-amylase).