In order to evaluate the sensitivity of the exocrine pancreatic function test employing a new synthetic peptide, N-Benzoyl-L-tyrosyl-p-aminobenzoic acid (BT-PABA), studies were performed on 18 control subjects, 14 patients with suspected chronic pancreatitis and 32 patients with chronic pancreatitis, comparing three oral doses: 0.5g BT-PABA, 1.0g BT-PABA and combined use of 0.5g BT-PABA and 50g of test meal (Sustagen). Patients with chronic pancreatitis showed signigicantly lower PFD values than control subjects regardless of the dose. Administration of 0.5g BT-PABA gave not only the best result in detecting exocrine pancreatic dysfunction, but also the highest correlation with the results of the PS test, followed by the 1.0g BT-PABA administration and then by the combined use of 0.5g BT-PABA and 50g Sustagen. The highest correlation coefficient was noted between the first two methods, whereas only a poor correlation was noted between the combined method and the other two methods. No improvement in sensitivity was attained by administering 1.0g BT-PABA or 0.5g BT-PABA in combination with test meal.