Background Craving is a core feature of addiction. Rumination and depression play a crucial role in the process of methamphetamine addiction. The aim of this study was to examine the relationship between rumination, depression and craving in methamphetamine patients, which has not been explored yet. Methods A total of 778 patients with methamphetamine user disorder (MUD) at the Xinhua Drug Rehabilitation Center, located in Mianyang City, Sichuan Province, China. We used a set of self-administered questionnaires that included socio-demographic, detailed drug use history, rumination, depression and craving information. The Rumination Response Scale (RRS) was used to measure rumination, the Beck Depression Inventory (BDI) to measure depression and the Visual Analogue Scale (VAS) to measure craving. Results There was a significant positive correlation between rumination and craving, or depression, and between depression and craving. Furthermore, depression mediated between rumination and craving, with a mediation effect of 160%. Conclusions Our findings suggest that there is a close interrelationship between rumination, craving and depression in MUD patients, and that depression may play a mediating role between rumination and craving.