Pinus koraiensis seed oil (pine nut oil), containing pinolenic acid, has been proposed as a beneficial fat by virtue of its effects on some lipid variables. In this study the effects of a pine nut oil-supplemented diet in mice, in comparison to control animals fed with a maize oil enriched diet, were investigated. Pine nut oil caused a significant reduction in body weight gain and liver weight (37.4 and 13.7%, respectively). An impressive decrease in plasma triglycerides and total cholesterol (31.8 and 28.5%, respectively) was also found in pine nut oil-fed animals. Liver lipids were also positively influenced by pine nut oil. The mitochondrial and cytosolic enzyme activities involved in hepatic fatty acid synthesis were strongly reduced both in pine nut oil and maize oil-fed animals, thus suggesting that the beneficial effects of pine nut oil are not due to an inhibition of hepatic lipogenesis.