Some of the major barriers to wide acceptance of fish oils as sources of polyunsaturated triglyeerides, fatty adds, and fatty acid derivatives have been the problems associated with color, odor, flavor, and other impurities. Adsorptive bleaching and molecular distillation were investigated as methods to obtain natural triglyeerides from menhaden oil that do not have undesirable flavors and odors. Results of these studies have shown that certain activated days will satisfactorily reduce the color of commercial menhaden oil but wilt not remove the odor and flavor. Molecular distillation was found to be more effective in improving the odor and flavor of the oil than adsorptive bleaching with activated clays but somewhat less effective in reducing' the color. When used jointly with bleaching, molecular distillation yields menhaden oil of high quality, suitable for use both in animal and human nutrition and in medical research. Spectral data in the 400-700 m~ range were used to evaluate the success of the refining process.