The accuracy of ultrasonographic examination combined with measurement of elastase 1 levels for early detection of pancreatic cancer was evaluated prospectively. Abdominal ultrasonographic examination and measurement of serum elastase 1 levels were done within 2 weeks after the initial visit to the clinic in a total of 2098 patients older than 35 years of age with symptoms suggesting pancreatic disease. Those in which one or both of these examinations had abnormal results underwent additional tests such as endoscopic retrograde cholangiopancreatography and computed tomography. Of those with pancreatosonograms with abnormal results with or without abnormally high serum elastase 1 levels, 19 patients eventually were found to have pancreatic cancer. No patients with pancreatic cancer, a normal level of serum elastase 1, and a pancreatosonogram with normal results were found, but follow-up studies revealed one pancreatic cancer in 189 patients after technically unsatisfactory ultrasonographic examination. In 9 (45%) of the 20 cases detected in this study, the pancreatic cancers were resectable, and two (10%) were less than 2.0 cm in longest diameter. These findings indicate that this combined examination is useful for early detection of pancreatic cancer. However, no pancreatic cancer was found in patients with abnormally high serum elastase 1 levels without a pancreatosonogram with abnormal results. Moreover, a combination of ultrasonographic examination and measurement of the elastase 1 level did not raise the diagnostic accuracy over that of ultrasonographic examination alone. These findings indicate that ultrasonographic examination alone is useful in screening for early pancreatic cancer.