A method for estimating the net cost of biochemical investigations has been developed as exemplified by the clinical laboratory of the N. N. Petrov Research Institute of Oncology of the USSR Ministry of Health. A data bank including information on the wages fund, cost of material used, equipment wear, and other expenditures was created for these estimations. Labor consumption for each of the 27 types of biochemical investigations comprised the production time of physicians (79.3 percent) and laboratory assistants (87.3 percent). Net cost of physicians' productive minute has made up 0.04 roubles, that of laboratory assistants' minute, 0.02 roubles. Wastes unrelated to the time of investigation were also taken into consideration.