A 68-year-old woman presented with an extremely rare brain abscess associated with old and acute hemorrhages manifesting as gradual onset of symptoms of headache and fever. Magnetic resonance imaging clearly visualized the hemorrhage as heterogeneously hyperintense on diffusion-weighted imaging, concentric hypo-isointense on T₁-weighted imaging, and homogeneously hyperintense with a hypointense rim on T₂^*-weighted imaging. T₁-weighted imaging with contrast medium revealed a well-enhanced cyst wall. In spite of treatment with antibiotics, the neurological status of the patient deteriorated due to expansion of the abscess and perifocal edema. Needle aspiration of the cyst yielded bloody purulent fluid. The magnetic resonance imaging findings indicate that neovascularization of the cyst wall is involved in the mechanism of hemorrhage in brain abscess. Careful follow-up examinations are recommended in patients with brain abscess to detect warning signs of neurological deterioration.