Recent literature suggests that serum amylase levels are not an appropriate screen for the diagnosis of acute pancreatitis because specificity and sensitivity are poor. Evidence from several studies supports the use of lipase determinations to diagnose acute pancreatitis, and recent improvements in this assay have made it more readily available to the emergency physician. This retrospective review compares the use of serum amylase to lipase levels in the diagnosis of acute pancreatitis in 52 patients who presented to the emergency department, with the hospital discharge diagnosis serving as the gold standard to which the assays were compared. Serum lipase was found to be more sensitive than serum amylase (95% vs 79%); serum amylase levels decreased to normal significantly faster than lipase levels.