Report Preface: This publication is a companion report to F. M. 40, "Labor Requirements for Crops and Livestock," published in May 1943. The basic labor requirements per acre and per unit of livestock contained in F. M. 40, and additional data were used in making the following estimates of total man-hours per month and per year required by each enterprise and by all farms in each State and in the United States. The main purpose of this report is to make available to research and extension workers, and to some other groups, the large amount of data on labor requirements that were computed in laying the foundation for the development of a new series that will measure farm labor in terms of man-hour requirements. These data are basic to an understanding of the reasons for the long-time shift from peak farm loads in midsummer to peak loads in the late summer and early fall months, and the reductions in labor requirements during the war. They are necessary to an analysis of the effects of technological developments on labor needed in agriculture. The State data make possible study and analysis of geographic variations in labor productivity and the effects of technological developments on amounts of labor needed.