Extra-phagosomal structures containing endogenous p67^phox are derived from azurophil and specific granules. Mouse neutrophils were incubated without (cells alone) or with IgG-opsonized 3-μm latex beads as described in “Phagocytosis assays” and were allowed to adhere on glass coverslips. Cells were fixed and permeabilized as described in “Phagocytosis assays,” stained with relevant antibodies, mounted, and visualized on a Zeiss LSM 510 META point-scanning confocal microscope. The position of the phagosome is indicated by a star. Arrows indicate the position of the p67^phox-positive extra-phagosomal structure and of granule markers colocalizing with this structure.