Cholesterol is an analyte commonly measured in various biological fluids. Enzymic procedures have virtually replaced the chemical methods for cholesterol determinations. Standardization of cholesterol assays often involve the use of solutions of this steroid containing organic solvents and/or detergents, or alternatively, the use of secondary standards. The present report shows the preparation of a primary cholesterol standard by its complexation with a chemically modified cyclodextrin. hydroxylpropyl β-cyclodextrin. The use of cyclodextrin for cholesterol solubilization is not deleterious to the enzymes and other constituents present in reagents for cholesterol analysis. Such a standard is biocompatible. stable, and safe and offers an excellent alternative to the utilization of organic solvents or detergents.