Cholesterol, triglyceride, and non-esterified fatty acid (NEFA) levels and lipoprotein electrophoretic patterns in blood plasma of ten species of wild rodents are compared with those of the laboratory mouse and man under standard conditions. 1. Average plasma lipid levels for the mouse and man appear in the middle of the wide ranges of 0.6-1.8 g/l. for cholesterol, 0.4 to 2.4 g/l. for triglyceride and 0.32-0.68 m-equiv/l. for NEFA found in these rodents suggesting species may vary in their ability to utilize these lipids. 2. Some universal relationship between levels of cholesterol and triglyceride, but not with NEFA, are suggested by a comparison between average levels in these 12 species. 3. Lack of correlation between the typical four component human lipoprotein electrophoretic pattern with any of the uniquely different patterns of rodents indicate using this method it is not feasible to compare the blood lipid transport system amongst species.