Postprandial hyperlipidemia (PH) is frequently observed in diabetic patients. We performed an oral fat-loading test in Zucker diabetic fatty (ZDF) fa/fa rats, a model for type II diabetes, to determine whether PH was induced in the rats. Post fat-loading changes in serum cholesterol and triglyceride levels were significantly greater in the fa/fa rats than those seen in their lean littermates and an acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor significantly reduced these levels by 24% and 31%, respectively. Therefore, we confirmed that PH appeared in ZDF fa/fa rats by fat loading and ACAT inhibition may be a potential treatment for PH.