The regression of diet-induced atherosclerosis in Güttingen Miniature Swine was investigated after a 6-month induction period. At 1 month after feeding a high-cholesterol and high-fat diet, levels of µ-lipoprotein, total cholesterol, free fatty acids and phospholipid had increased rapidly and the high levels were maintained throughout the 6 month induction period. Morphological features at 6 months showed fatty streaks in the thoracic aorta and fibrous plaques in the abdominal aorta. After return to the conventional diet at 6 months, serum lipids decreased rapidly and maintained the baseline level throughout the 9 month regression period. Histopathological findings showed the regression of fatty streaks but the fibrous plaques did not regress. The present study therefore confirms the regression of fatty streaks in the aorta of Güttingen Miniature Swine by the administration of a cholesterol lowering diet.