During the 45 month period beginning January 1977, 251 patients with a pathologically confirmed diagnosis of acute appendicitis underwent celiotomy at the Medical College of Virginia Hospital. A preoperative serum or urine amylase determination was recorded in 155 of the patients (62 percent). Of this group, 15 patients (10 percent) had elevation of serum amylase or 2 hour urine amylase. Hyperamylasemia or hyperamylasuria directly led to misdiagnosis or treatment delay in 5 of the 15 patients. Appendiceal rupture occurred in three patients, two of whom had prolonged (greater than 1 month) hospitalizations directly attributable to the misdiagnosis. As a result of this study, we conclude that (1) acute appendicitis and elevated amylase levels may occur concurrently, (2) hyperamylasemia or hyperamylasuria should not dissuade the surgeon from early operation if other clinical features suggest appendicitis, and (3) abdominal pain and elevation of amylase level define significant intraabdominal disease, not specifically pancreatic disease.