jats:pThis article discusses the uses of mud in Central Asian cities with specific reference to this building material’s role in views on the Mongols’ westward conquests from 1219 to the 1250s. Outlining the patterns of construction, maintenance, and reconstruction of earthen architecture, I consider how the Mongol conquests would have impacted the urban occupation of cities that relied on this building material with a focus on examples from Merv, Turkmenistan, and Otrar, Kazakhstan. Given the need for continuous maintenance to mud-brick architecture to prevent decay, and the difficulties of reversing this process once it has begun, I argue that depopulation resulting from the Mongol conquest campaigns would have impacted the urban fabric more significantly than any deliberate demolition by invading Mongol armies. Based on archaeological analysis, I discuss the practicalities and difficulties of reusing mud as a building material to show that the abandonment of buildings and cities can be a conscious, pragmatic response to erosion or a shifting water supply rather than a catastrophic event. I conclude that thirteenth-century accounts describing the urban devastation and demolition of Central Asian cities should be reconsidered to include the collateral impact of the flight of populations and environmental change, as evidenced in the archaeological record.</jats:p>