Three methods for the isolation of Cheddar cheese flavor (distillation, dialysis, and solvent extraction) were compared. The solvent extraction (acetonitrile) method gave the least concentrated isolate. It was, however, the fastest and cheapest and gave the most characteristic flavor isolate of the three techniques. Dialysis yielded the most concentrated flavor isolate. The gas chromatographic effluent was sniffed to determined odor character of the volatiles isolated. Many odor-active compounds, some of them in concentrations below the detection threshold of the analytical instrument, contribute to Cheddar cheese flavor. While one component was characterized as being cheesy in character, we feel that Cheddar cheese derives its characteristic flavor from a balance of many components. Four chemicals, 2-pro-panol, 1,3-butanediol, δ-undecalactone, and ɣ-decalactone, were tentatively identified in Cheddar cheese for the first time.