We present an unusual case of gliosarcoma containing numerous islands of well-differentiated melanocytes in a 65 year-old man. Melanocytic differentiation of medulloblastomas is well described, and it has also rarely been reported in low-grade glial neoplasms. Histologic features and immunophenotyping are helpful in differentiating divergent differentiation in a gliosarcoma from melanoma. To our knowledge, this is the first description of a gliosarcoma with melanocytic differentiation. Awareness of the phenomenon of melanocytic differentiation within primary neuroepithelial and glial neoplasms is important to prevent the misdiagnosis of these tumors such as metastatic melanoma or primary melanocytic neoplasms of the CNS.