Technical Abstract: The limited volume of plasma available from small animal favors micro methods of analysis. Hamster and human plasma lipoproteins were fractionated using size exclusion chromatography followed by an inline post column enzymatic reactor and results compared with the sequential density ultracentrifugation method. Correlation coefficients between the two methods for hamster and human HDL, LDL and VLDL ranged from 0.90 to 0.95. Enzymatic post column detection of cholesterol increases the sensitivity of the method over UV detection of apolipoprotein. This method is especially suitable for small animals where only microliters of plasma may be available.