Adenofibroma is a rare benign biphasic neoplasm that is classified into the mixed epithelial and mesenchymal tumor group. We report the case of a 42-year-old woman with adenofibroma of the endometrium protruding into the vagina. Transvaginal ultrasonography revealed the tumor as an intravaginal mass containing multiple cystic components. Magnetic resonance imaging (MRI) showed a heterogeneous high-intensity mass filling the vaginal cavity on T2-weighted imaging, with a low-contrast enhanced septum identified within the mass on gadolinium-enhanced, T1-weighted imaging. Contrast-enhanced computed tomography (CT) showed a heterogeneous low-attenuating multicystic mass filling the vaginal cavity. Although preoperative diagnosis of this rare tumor is very difficult, the combination of MRI, CT, and ultrasonography offers a useful diagnostic tool.