Three of the major problems connected with rainbow trout production and management were studied at Paul Lake, British Columbia: (1) what quantity of fish can be produced in a given body of water, (2) how big a crop can be removed and still allow a sustained yield, (3) how great a financial expenditure to increase production may be justified. The investigation covered a period from 1931 through 1936 in which a consistent stocking policy requiring the planting of 200,000 one-inch fry was carried out. The data show that the lake was capable of producing about 10 pounds of trout per acre and that this amount is being maintained under the policy outlined. The mortality amounted to about 95 per cent, providing a 5 per cent yield to the fishermen. The cost of the stocking operations was judged to be commensurate with the return to the people of the Kamloops District. It is suggested that intensive management of this type should be instituted only after adequate surveys have been made of individual bodies of water.