Abstract: Since the beginning of the novel coronavirus disease (COVID-19) pandemic, many papers have been published about the association between COVID-19 and various endocrine abnormalities. Accumulated data so far reveal that hyperglycemic conditions such as the deterioration of glycemic control and ketoacidosis in diabetic people, and new-onset diabetes mellitus become prominent as the mainly endocrine manifestations of this disease. However, it has not yet been clearly described the potential negative impacts of COVID-19 on the pituitary gland. Herein we present a 41-year-old man with diabetes mellitus that diabetic ketoacidosis and transient hypopituitarism developed simultaneously following COVID-19. We aimed to emphasize via this report that COVID-19 may be associated with not only hyperglycemia but also pituitary dysfunction, even such endocrine complications may also occur in the same patient as in our case.