Hyperamylasemia is a common finding in chronic renal failure (CRF) patients. The present study was designed to evaluate the frequency, the type, and the hyperamylasemia levels in renal transplant recipients (RTR) compared to patients with renal failure with or without replacement of renal function. One hundred and forty-one subjects [42 with varying degree of renal insufficiency (group A), 74 on hemodialysis (group B), and 25 RTR (group C)] and 47 normal individuals were studied. Total serum alpha-amylase (Ta) as well as pancreatic (Pa) and salivary (Sa) types of serum isoamylases were elevated in all groups when compared to the levels found in normal subjects. A remarkable proportion of patients belonging to groups A and B had Ta as well as Pa levels over three times the upper normal limits. On the contrary, no RTR had such increased levels of both Ta and isoamylases. A statistically significant correlation was found between Ta, Pa, and Sa and serum creatinine in RTR. However, no statistically significant correlation was found between urine amylases and serum creatinine or between urine and serum levels in all amylases in this group. In conclusion, serum amylase levels are increased in RTR. However, no subject in this group had amylase and isoamylase values more than three times the upper normal limits, which was a common finding in the other groups of patients.