Visual sizing of cantaloupes for commercial marketing results in considerable variation among melons within packed shipping containers. This situation causes losses to retail grocers, who must pay for the additional labor needed to differentially price the various sized melons—and to sustain losses from the sale of undersized melons within packs. Attempts to measure cantaloupe volumes by diameters have not proved satisfactory. Results of this study of cantaloupe volume: weight relationships conducted during 1965–67 indicated that fruit weights could serve as an accurate measure of volume. This correlation was determined in a series of volume: weight relationship studies during the 1965, '66, and '67 seasons for PMR-45, the most commonly grown variety in California; for several commercial varieties grown under comparable conditions in a variety test plot at the University of California's West Side Field Station, and for Top Mark, a recently introduced commercial variety grown in the Imperial and San Joaquin valleys.