Melon (Cucumis melo L.; 2n = 2x = 24) is a major cucurbit vegetable crop cultivated globally. The andromonoecious sex form is predominant in muskmelon, and the occurrence of many other pollination mechanisms, such as monoecy, gynoecy, and genetic male sterility, has enabled rapid improvement in the exploitation of F1 hybrids. Hand emasculation and hand pollination are required if the female parent is andromonoecious. The advantages of the male sterile mechanism in cucurbits include strong protection of breeders’ rights, comparative stability in the performance of resulting hybrids, and ease of maintenance. This chapter provides an overview of the progress and breeding advancements of muskmelon using the male sterility system.