This study investigated the short-term effects of the triglyceride (TG), free fatty acid (FFA), ethyl ester (EE), and phospholipid (PL) forms of docosahexaenoic acid (DHA) on the absorption of omega-3 fatty acids (FA) into tissues. Male Balb/c mice were fed a low-fat (LF, 5%) or high-fat (HF, 22.5%) diet containing different formulations of 0.7% omega-3 fatty acid for 1 week. The fatty acid compositions of the liver, adipose tissue, gastrocnemius muscle, and brain were determined. After 1 week, TG-, FFA-, and PL-DHA increased the concentration of DHA in the livers of mice fed LF diet. The hepatic DHA concentration also increased significantly in the HF-TG and HF-PL groups (39.7% and 45.0%, respectively; p < 0.05). In adipose tissue, the DHA levels in mice fed LF-DHA diets were all elevated; the same trend was observed in the HF-DHA diet groups. The proportion of DHA in the gastrocnemius muscle in the LF-DHA diet groups was higher than that in the LF-control group, but no marked increase was observed in the HF-DHA diet groups. In the gastrocnemius muscle, all DHA forms significantly increased the DHA content in mice fed an LF diet; in mice fed an HF diet, EE-DHA and PL-DHA significantly increased the concentration of DHA. No significant changes were observed in the cerebral DHA content when the various forms of DHA were added to the LF diet. However, FFA-, EE-, and PL-DHA increased the cerebral concentration of DHA significantly when added to an HF diet. The present study suggests that the molecular form of DHA contributes to the effects of omega-3 polyunsaturated fatty acids on lipid metabolism. DHA-PL and DHA-TG were more efficient than other DHA forms in increasing the omega-3 concentration in mouse organs.