This method for the hydrolysis of estrogens completes the automated analysis of estrogens in pregnancy urine described by Muir, Ua Conaill, and Ryan [Steroids 13, 719 (1969)]. Pregnancy urines can be processed from the sampling of urine to the recording of fluorescence intensity in 30 min, at a rate of 20 samples per hour. The presence of glucose does not decrease the apparent hydrolysis products.