A simple and convenient method to determine plasma cholesterol profiles in individual mouse plasma samples is not presently available. With commonly used methods, plasma samples from several animals in a study group must often be pooled and analyzed, usually by the fast phase liquid chromatography (FPLC) method. The Column Lipoprotein Profile (or CLiP) method described here is a modification of the FPLC method that provides a simple and convenient procedure for determining plasma lipoprotein cholesterol profiles in small sample volumes, allowing determination of profiles from individual animals rather than from pooled plasma. The CLiP method is reproducible; a human sample measured five times over several days produced coefficients of variation as follows: VLDL, 10.0%; LDL, 0.93%; and HDL, 2.51%. CLiP-derived total cholesterol values of five different human samples (with total cholesterol levels ranging from 198 to 263 mg/dL) differed from VAP-II by -1.88% +/- 2.57%. Linearity of differing concentrations for each of the lipoprotein classes was determined by measuring the same sample with different aliquot sizes. The linear regression from VLDL had an r value of 0.996, while LDL, HDL, and total cholesterol all had r values of greater than 0.999. We present a direct comparison of plasma cholesterol profiles from several mouse models with gene modification or expression of transgenic proteins. In conclusion, the CLiP method provides a simple, reliable, and reproducible procedure for determination of plasma cholesterol profiles from individual plasma samples with very low sample volumes, using readily available equipment and reagents.