The diagnosis of chronic pancreatitis usually is based on imaging studies, pancreatic function tests, and the presence of characteristic clinical features. In Japan, diagnostic criteria for chronic pancreatitis were established in 1983 and revised in 1995. Under the new criteria, the secretin test (a duodenal intubation test) and the combination of noninvasive tests, N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BT-PABA) and fecal chymotrypsin (FCT), have been recommended for evaluating exocrine pancreatic function in patients with chronic pancreatitis. In the present study, the diagnostic value of these two noninvasive tests was compared to the secretin test. Although noninvasive tests are less sensitive and specific for determining exocrine pancreatic impairment than the secretin test, greater reliability for diagnosing chronic pancreatitis can be obtained by performing the BT-PABA and fecal chymotrypsin tests simultaneously. Combining BT-PABA and FCT is easy and useful and should be performed at least twice to obtain reliable results.