A 35-year-old female presented with a cavernous angioma of the septum pellucidum manifesting as headache and nausea. Computed tomography and magnetic resonance imaging revealed a mass at the septum pellucidum with intraventricular hemorrhage and mild hydrocephalus. Digital subtraction angiography showed no abnormal finding and thallium-201 single photon emission computed tomography showed no uptake in the lesion. The preoperative diagnosis was intraventricular tumor, such as subependymoma. The lesion was completely resected through the transcallosal approach. The histological diagnosis was cavernous angioma. Cavernous angiomas are usually located in the cerebral parenchyma and rarely occur in the cerebral ventricles. In particular, cavernous angioma at the septum pellucidum is very rare. If magnetic resonance imaging does not clearly show the typical peripheral hypointense rim, neuroimaging diagnosis will be difficult. Surgical resection should be considered to confirm the histopathology, in particular if bleeding and hydrocephalus are present.