Abstract: 94 cases of pituitary adenomas were examined by radioimmunoassay, immunohistochemical and electron microscopic techniques, Among them, 36 cases associated simultaneously with hypersomatotropinemia and hyperprolactinemia were studied. The result showed that they could be classified into four types: （1） Mixed growth hormone and prolactin cell adenomas; （2） Acidophil stem cell adenomas; （3） Plurihormonal adenomas; and （4） Growth hormone adenomas. The pathological and clinical characteristics were discussed.