A brain abscess complicated antineoplastic chemotherapy for a primary cerebral rhabdoid tumor in an immunocompromised boy. Culture of purulent exudate obtained by surgical puncture of an intracranial hematoma yielded a gram-positive microorganism initially identified as a Rhodococcus species by conventional biochemical analysis; however, the isolate was subsequently identified as Gordona terrae by ribosomal DNA analysis. To our knowledge, this is the third case of human infection caused by G. terrae and the first case of a brain abscess due to this organism. As this case demonstrates, this species may cause opportunistic invasive infection in severely immunocompromised patients. The identity of clinical isolates believed to be G. terrae should be confirmed by molecular methods until better species-specific phenotypic markers become available.