The coefficient of correlation between values for urinary 20-oxosteroids and urinary cortisol was 0.75 in 106 24-hours urines. Urinary cortisol was usually the more specific and sensitive parameter for the evaluation of adrenocortical function. With an analysis time of 4-5 hours for 100 samples, the method for cortisol was also faster and cheaper. Furthermore, the intra- and interassay variances of 2.7 and 8.2%, respectively, indicate high precision.