RATIONALE:: Mucormycosis is a rare fungal infection most commonly seen in immunocompromised patients or those with poorly controlled diabetes mellitus. Mucormycosis is exceedingly rare in immunocompetent hosts. PATIENT CONCERNS:: We present an unusual case of isolated cerebral mucormycosis in a young injection drug user. DIAGNOSIS:: The diagnosis of cerebral mucormycosis was made using stereotactic brain biopsy and tissue culture. INTERVENTIONS:: The patient was treated with a combination of amphotericin B and anidulafungin. OUTCOMES:: Although the patient experienced residual neurologic deficits, she was able to resume many independent activities. LESSONS:: Although isolated cerebral mucormycosis is rare, it has an extremely poor prognosis. The most significant risk factor for isolated cerebral infection is injection drug use, which is likely secondary to the injection of drugs contaminated with Rhizopus spores. These patients typically present with brain abscesses in the basal ganglia. In critically ill patients and in those who fail polyene monotherapy, a combination of amphotericin B-anidulafungin therapy may provide survival benefits. Further study of synergy and combination therapy for isolated cerebral mucormycosis must be conducted before clinical conclusions can be drawn.