Ten patients with pituitary apoplexy were treated at the Institute of Endocrinology, Gerontology and Geriatrics in Sofia over the last 5 years. They represented 5.06% of the total number of patients with pituitary adenomas treated at the Institute during the same period. The highest frequency of pituitary apoplexy was noted among patients with Nelson's syndrome. In 5 patients of this group pituitary apoplexy was the first sign of a tumor. Headaches combined with nausea and vomiting were the earliest symptoms of pituitary apoplexy, and ptosis and ophthalmoplegy were the most common symptoms in the patients. The disease was not correctly diagnosed in 7 patients who immediately after apoplexy were treated in neurological and ophthalmological departments.