Stimulated neutrophil is the main source of oxidants/free radicals, that might contribute to the state of oxidative stress. Coffee has been well known to have a high antioxidant capacity, therefore it was plausible to hypothesize that coffee might reduce oxidants/radicals produced by neutrophil. This study aimed to analyze effect of coffee on superoxide radical produced by neutrophil in vitro. This study was conducted experimentally using the post test only control group design. Neutrophil was isolated from healthy human peripheral blood. Superoxide radical production was analyzed by NBT (nitro blue tetrazolium) assay. Results showed that coffee significantly (P < 0.05) reduced the number of neutrophils that produce superoxide radicals. In conclusion, coffee demonstrated antioxidant capacity against neutrophil superoxide radicals.