The macrophage receptors for the Fc portion of immunoglobulin G (FcgammaR) have long been known to mediate a variety of effector functions that are vital to the adaptive immune response. Recent studies, however, have begun to stress potential regulatory roles that these receptors can play in modulating immune and inflammatory responses. In this article we discuss the activating and inhibitory properties of the individual macrophage FcgammaR and the conditions under which these heterologous responses can occur.