Background: Meningiomas are mostly benign intracranial tumours. Diaphragma sallae meningiomas are rare and may be hard to differentiate from pituitary denomas.We report a rare case of diaphragma sellae meningioma mimicking pituitary macroadenoma in a 32-year-old man. Case Presentation: The patient was admitted to Ahwaz Golestan Hospital with a 2- year history of headache, especially at night. Also, he had a bilateral ocular pain with visual field defects. Endocrinology examination revealed hyperprolactemia. His cranial radiographs revealed an enlarged sellae turcica and destruction of dorsum sellae. Computed tomography (CT) reveals a homogeneous, enhancing, and isodense mass in the intra- and suprasellar lesion without calcification. Magnetic resonance imaging (MRI) showed a solid mass with well defined margin. This mass was isointense on both T1 and T2 weighted images and homogeneously enhanced. The preoperative diagnosis was pituitary macroadenoma. A transsphenoidal rinoseptal approach was used. The specimen consisted of fragments of brownish soft tissue. External surface was irregular. Sections showed a lesion compound spindle cell proliferation with dense nucleus and scanty cytoplasm with whorling pattern, which suggested meningioma (fibrous type). Conclusion: It is necessary to distinguish diaphragm sellae meningioma from pituitary macroadenoma for the appropriate surgical approach and to subsequently decrease the complications from surgery. © 2010 Rasras S, Alemzadeh Ansari MJ, Alemzadeh Ansari MH, Rahbarian F, Rashidi I.