OBJECTIVE: This study was designed to evaluate the clinical, radiologic, histologic, and surgical outcome characteristics of this disease treated in a single institution. METHODS: Sixteen adult patients underwent transsphenoidal microsurgery from October 2005 to December 2010 at Neurosurgical Center of Beijing Tiantan Hospital. The clinical, radiological, operative, and pathological findings of the patients were reviewed retrospectively. RESULTS: Pituitary dysfunction was presented in 12 patients, visual acuity and/or field deterioration in 11 patients, and headache in 8 patients. Hyperprolactinemia was presented in 7 of 9 female patients. All lesions were resected by transsphenoidal microsurgery as the primary procedure. A gross total resection was achieved in 3 of 16 patients, a radical subtotal resection in the remaining 13 patients. Nine cases were histologically classified as adamantinous subtype. After a mean follow-up of 50 months, 2 patients experienced recurrence. All female patients who had hyperprolactinemia experienced a gain of function postoperatively. Six patients experienced new diabetes insipidus. Visual field improved or normalized in 8 of 9 patients. Visual acuity improved in 1 case, and worsened in 1 patient. CONCLUSIONS: Primary adult infradiaphragmatic craniopharyngiomas are relatively rare lesions occurring in young adults. Pituitary dysfunction, visual acuity and/or field deterioration, and headache were the most common chief symptoms. Transsphenoidal surgery, including tearing the cyst walls off the diaphragma sellae and protecting normal pituitary tissue as much as possible, is recommended. Although at the risk of impairing the function of anterior pituitary, transsphenoidal surgery results in a high rate of both visual field and hyperprolactinemia improvement with a low associated risk of recurrence. In terms of pathological aspects, the adamantinous subtype was more common.