Fifty-three cases of brain abscess were treated at Mackay Memorial Hospital from January 1991 through December 2001. The ages ranged from 2 weeks to 84 years, with a peak at 40 to 50 years (11/53, 21%). The male to female ratio was 1.8:1 (34 males, 19 females). The most common presenting symptoms were fever (30/53, 57%), headache (29/53, 55%), and changed mental status (24/53, 45%). The duration of symptoms before hospitalization ranged from several hours to 2 months. A shorter duration of symptoms was associated with poor outcome. The common predisposing factors were otic infection (10/53, 19%), penetrating head trauma and neurosurgery (10/53, 19%), and bacterial endocarditis (5/53, 9%). The leading underlying diseases were diabetes mellitus (12/53, 23%) and/or liver cirrhosis (6/53, 11%), and both were independently associated with increased risk of mortality. Computed tomographic scanning and magnetic resonance imaging facilitated early diagnosis and proper management. Surgical intervention was used together with antibiotics in 33 (62%) of 53 patients in whom the average abscesses diameter was 3.75 cm (range, 2-6 cm). The remaining 20 (38%) patients whose average abscesses diameter was 2.3 cm (range, 1-3.5 cm) were treated with antibiotics only. Culture of material drained from abscesses isolated 27 microorganisms from 19 (58%) of the 33 patients, 81% (22/27) of which were aerobic and 19% (5/27) anaerobic bacteria. The most common pathogen was alpha-hemolytic Streptococcus spp. (6/27, 22%). Most of the patients with Klebsiella pneumoniae isolated from brain abscess, cerebrospinal fluid, and blood cultures were diabetic. A high mortality rate (9/20, 45%) was found in patients with medical treatment. A high index of suspicion is needed for the early diagnosis of brain abscess, particularly in patients with predisposing factors. In this series, early diagnosis using computed tomography and/or magnetic resonance scanning, optimal timing of surgery, and appropriate use of antibiotics were associated with improved outcome.