Choroid plexus papilloma (CCP) is an uncommon benign neoplasm of the neuroectoderm. We present the 18F-fluoro-2-deoxy-D-glucose (FDG) and 11C-methyl-L-methionine (methionine) positron emission tomography of CPP in comparison with that of low-grade glioma. Patients were two women and one man (20, 23, and 72 years old). The Ki-67 labeling index ranged from 0.98 to 2.22%, and histologically the cases belonged to grade 2. On quantitative analysis, the tumor/normal ratio (T/N) was calculated using the standardized uptake value. Methionine T/N was significantly higher in CPP (3.24+/-0.69) than in low-grade glioma (1.23+/-0.81; p<0.01), although no clear difference could be determined for FDG T/N between the two (0.87+/-0.39, 0.75+/-0.53). These results may suggest that the metabolism of amino acid in CPP is quite different from that in low-grade glioma.