One known effect of long chain n-3 polyunsaturated fatty acids is their ability to decrease plasma triglycerides. However, identification of the specific n-3 fatty acids and the underlying mechanisms responsible for this change remains uncertain. This present study was designed to evaluate the effects of moderate levels of dietary docosahexaenoic acid (22 :6(n-3)) on modulating plasma triglyderides. Male CD-1 mice were maintained for 15 days on identical diets containing either docosahexahexaenoic acid ethyl ester(1.5%, w/w) or linoleic acid(18 : 2(n-6)) ethyl ester (1.5%, w/w) . Plasma triglycerides were 40% lower in the docosahexaenoic acid group than in the linoleic acid group. Hepatic carnitine palmitoyltransferase activity (a key regulatory enzyme for mitocondria $eta$-oxidation) was not significantly different between the dietary groups. However, plasma acid soluble acylcarnitine levels (which increase with increasing $eta$-oxidation )were significantly higher in the decosahexaenoic acid group. This data suggests that plasma triglyceride levels are lower in mice fed diets containing moderate levels of docosahexaenoic acid compared to linoleic acid, but this effect on plasma triglycerides is not modulated through an augmentation of mitochondrial $eta$-oxidation.