The aim of the study is to retrospectively investigate the usefulness of 11C-acetate (ACE)-positron emission tomography (PET) for evaluation of brain glioma, in comparison with 11C-methionine (MET) and 2-deoxy-2-18F-fluoro-d-glucose (FDG). Fifteen patients with brain glioma referred to initial diagnosis were examined with ACE, MET, and FDG-PET. Five patients had low-grade gliomas (grade II), three had anaplastic astrocytomas (grade III), and seven had glioblastomas (grade IV). PET results were evaluated by visual and semiquantitative analysis. For semiquantitative analysis, the standardized uptake value (SUV) and tumor to contralateral normal gray matter (T/N) ratio were calculated. The sensitivity for detection of high-grade gliomas was calculated using visual analysis. Sensitivities of ACE, MET, and FDG were 90%, 100%, and 40%, respectively. ACE and MET T/N ratios were significantly higher than that of FDG. ACE and FDG SUV in high-grade gliomas were significantly higher than that in low-grade gliomas. No significant differences were observed using MET. ACE PET is a potentially useful radiotracer for detecting brain gliomas and differentiating high-grade gliomas.