The following study was presented to investigate the anti-inflammatory effect of peel extracts (PE) from three citrus fruits: Citrus unshiu, Citrus limonia Osbeck and Citrus hallabong. According to this study, cytotoxicity, NO-production and protein levels of iNOS (inducible nitric oxide synthase) in macrophage cell were analyzed, which had been incubated in murine macrophage cell line RAW 264.7 cell of PE from those three citrus fruits. According to Citrus unshiu peel extracts (CUP), Citrus limonia Osbeck peel extracts (CHP) and Citrus hallabong peel extracts (CLP) treatment, the result showed that there was no cell growth inhibited below 2 mg/mL. Comparing the NO-production of the cell with LPS (100 ng/mL) and the treatment without LPS, significant increase of NO-production was detected. However NO-production also showed decrease trend, as the concentration increased. For each treatment, at the concentration of 1 mg/mL, NO-ihibitory activity showed significant result with following order: CUP > CHP > CLP. According to the result from Western blot, the inhibitory activities of iNOS protein from CUP and CHP showed fairly similar performances. Also inhibitory activity of COX-2 showed the following order: CUP > CHP> CLP. There was no doubt that all the treatments of CUP, CHP and CLP have anti-inflammatory effect and also that the inhibitory activity of the CUP treatment was the strongest among those three.