Diagnosing primary cerebral nocardiosis is difficult. This case report describes a 79-year-old immunocompetent Japanese woman with a primary brain abscess caused by Nocardia otitidiscaviarum (IFM 11321) and reviews the findings of 11 previous patients with N. otitidiscaviarum-induced brain abscesses. Four patients survived, including ours. Beta-lactams were not effective in our patient, and the diagnosis required a pathologic analysis of the surgical specimen. Sulfamethoxazole/trimethoprim (ST) was administered to the patient. On antibiotic susceptibility testing, N. otitidiscaviarum (IFM11321) was found to be resistant to amoxicillin-clavulanic acid, ceftriaxone, cefotaxime, cefepime, imipenem and clarithromycin, but sensitive to amikacin, gentamicin, ST and linezolid. Antimicrobial susceptibility patterns differ among Nocardia species, making species identification important for treatment. Patients with suspected Nocardia infection should therefore be treated empirically with ST and/or amikacin and considered for surgical management.