Quantitative estimation of phenol content in human urine involving Gibbs reagent was described in detail; the procedure was applied for screening test of people. The Gibbs reagent was synthesized from commonly available substances 2,6-dibromine-4-aminophenol and 4-nitrophenol. Estimation of total and bound forms of phenol was carried out in 0.5 ml of urine, while phenol conjugates were hydrolyzed by means of heating of urine samples containing 0.2 ml of 42% perchloric acid in boiling water bath and the phenol released was extracted by 3.0 ml of diethyl ether. Sensitivity of the procedure was about 0.1 micrograms of phenol in a sample, when microphotometer, applied in immunological studies, was used for measurement of optic density in the plates holes. Content of total phenol was estimated in urine of 15 children of 6-6.5 years old from Moscow using the procedure developed and it constitute from 2.5 micrograms/ml to 47.0 micrograms/ml, middle value was 9.5 micrograms/ml. In 47 children from Noyabrsk town these parameters constituted 1.5 micrograms/ml, 150 micrograms/ml and 19 micrograms/ml, respectively in adults - 1.5 micrograms/ml, 168 micrograms/ml and 167.7 micrograms/ml, respectively. The upper limit of the phenol normal concentration in urine was proposed to be as 50 micrograms/ml in screening test of people. Content of phenol in urine should be measured within a day during individual examination.