This manuscript describes methods for the quantitation of serum concentrations of 17-hydroxyprogesterone and 11-deoxycortisol (Compound S) employing reverse-phase high-performance liquid chromatography (HPLC) and ultraviolet (UV) absorbance which are applicable to the diagnosis of congenital adrenal hyperplasia due to deficiencies of 21- and 11-hydroxylase activities, respectively. These methods are simple, specific, precise and rapid. Data obtained by the HPLC-UV methods are highly correlated (p less than 0.001) with radioimmunoassay measurements.