Fruit cracking is an important disorder that can cause severe loss of marketable yield and revenue in the muskmelon ( Cucumis melo ) fruit industry. The physiological and environmental factors causing cracking are poorly understood. Although generally considered a physiological disorder caused by fluctuating environmental conditions, current evidence indicates that this disorder also has a genetic as well as a genotype × environment component. Certain cultivars are more susceptible than others, but wide fluctuations in irrigation, temperature, and nutrition during late fruit maturation stages appear to predispose fruit to cracking. This article summarizes the current state of our understanding of the causes of fruit splitting in muskmelons.