Murine resident peritoneal macrophages can produce potent reactive oxygen species (ROS) and arachidonic acid metabolites such as eicosanoids, which have important roles in host defense and the pathogenesis of inflammation. Phagocytosis and macrophage activation are believed to enhance secretion of ROS and eicosanoids. Therefore, we investigated the influence of ROS release on arachidonate mobilization. Our results shown that ROS could be involved in the pathways that result in [3H]AA release. We suggested that phosphorylation and dephosphorylation processes stimulated by ROS could increase arachidonic acid mobilization via a PKC-independent pathway.