Autoimmune polyendocrinopathy type II is rarely reported in Chinese patients. A 42-year-old Chinese woman with a history of Hashimoto's thyroiditis and hypogonadotropic hypogonadism presented with pneumonia. During hospitalisation, she went into an adrenal crisis and diabetic ketoacidosis. Subsequent dynamic hormonal tests revealed primary and secondary adrenal insufficiency. She also had pernicious anaemia, possible alopecia areata, and myasthenia gravis. This constellation of multiple endocrine and non-endocrine disorders led to the diagnosis of autoimmune polyendocrinopathy type II. As the syndrome can be lethal, it is important to maintain a high index of suspicion, enabling early diagnosis and the appropriate replacement therapy, to ensure a successful outcome.