Lipid and lipoprotein concentrations and apolipoprotein profile were investigated in canine pancreatitis induced by infusion with oleic acid (OA) into the accessory pancreatic duct. Pancreatitis was diagnosed by physical, hematological, biochemical and pathological examinations. In OA-treated dogs, serum triglyceride (TG) concentration was increased; however, there were no changes in serum total cholesterol (TC) and phospholipid (PL) concentrations. Serum concentrations of TG, TC, PL and total lipids (TL) in beta lipoprotein and those of TC, PL and TL in pre-beta lipoprotein were increased and those of TC, PL and TL in alpha1 lipoprotein were decreased. In apolipoprotein profile, the proportions of apolipoprotein B100 in low density lipoprotein fraction and apolipoprotein A-IV in high density lipoprotein fraction were increased. In addition, decreased proportion of apolipoprotein A-I and the appearance of serum amyloid A protein in high density lipoprotein fraction were observed. These results suggest that lipoprotein profiles observed in canine acute pancreatitis are attributed to the alterations in apolipoprotein compositions.