Marxists from all disciplines are hostile toward 'empiricism,' viewed as the conception that knowledge is derived solely from measurement and observation which lacks any a priori notions of causation. On the other hand, Marxist criminology is criticized for lacking empirical support. A central Marxist concept is 'surplus value,' which is Marx' measure of the exploitation of labor. The importance of measuring surplus value in the context of Marxist criminology is the theoretical link between surplus value and crime and punishment. This article describes how surplus value can be measured and mathematically calculated. The data necessary to perform the proposed calculations are available in the U.S. Census of Manufacturers, the Historical Abstracts of the United States, and the Annual Survey of Manufacturers. 2 tables, 14 notes, and 87 references.