Donkey metabolic syndrome (DMS) and pituitary pars intermedia dysfunction (PPID) are the most common endocrine disorders in donkeys and mules. However, other less frequent disturbances such as calcium and phosphorus imbalances or thyroid gland disorders can also be observed. There is recent information on the diagnosis and treatment of PPID, DMS, obesity, and hyperinsulinemia-associated laminitis; however, fewer studies compared to horses. In mules, there is a lack of information on endocrine disorders. This chapter compiles endocrine information available in donkeys and mules.