Serum lipid and apolipoprotein (apo A-I, A-II, A-IV, B, C-II, C-III, E and H) levels were determined in 26 patients with chronic pancreatitis without complications such as liver disease or diabetes mellitus. These patients were divided into two groups, CP-I (n = 16) and CP-II (n = 10), according to the clinical criteria for chronic pancreatitis. HDL-cholesterol and apo A-I levels in CP-I and CP-II groups significantly decreased compared to those in sex- and age-matched healthy controls (p less than 0.05), whereas there were not significant differences in triglyceride and total cholesterol levels between these groups and controls. On the other hand, apo A-IV levels in CP-I and CP-II were 7.1 +/- 1.0 mg/dl and 8.3 +/- 1.5 mg/dl, respectively and these values were significantly lower than 11.2 +/- 1.8 mg/dl in controls (p less than 0.001). In this study, the serum lipids apparently showed normal levels in patients with chronic pancreatitis who had no severe complication, and the markedly low apo A-IV levels in these patients were considered to be mainly due to the decrease of lipid absorption from the intestine.