Large tumors invading the dorsal part of the anterior third ventricle are difficult to manage. The anterior transcallosal approach is usually used to manage these tumors. In our clinic, anterior callosal section was combined with the anterior interhemispheric (AIH) translamina terminalis approach for these tumors with excellent results. The AIH approach is useful for removing tumors in and around the anterior part of the third ventricle. However, AIH alone is insufficient for large tumors invading the dorsal part of the anterior third ventricle. In such situations, simple anterior callosal section enables the neurosurgeon to extirpate the caudal part of the tumors deeply hidden from operative field, sparing the foramen of Monro, fornix, etc. We treated four large tumors (malignant teratoma, recurrent chordoid glioma, recurrent papillary tumor of pineal region occupying the third ventricle, and paraventricular meningioma) without major complications. The malignant teratoma case exhibited no recurrence with >10 years follow-up. The chordoid glioma and papillary tumor of pineal region were totally removed. The meningioma was subtotally removed except only a small tumor around the bilateral anterior cerebral artery. This simple technique is a new way to manage difficult large lesions in and around the third ventricle.