Phagocytosis - the process by which macrophages, dendritic cells and other myeloid phagocytes internalize diverse particulate targets - is a key mechanism of innate immunity. The molecular and cellular events that underlie the binding of targets to a phagocyte and their engulfment into phagosomes have been extensively studied. More recent data suggest that the process of phagocytosis itself provides information to myeloid phagocytes about the nature of the targets they are engulfing and that this helps to tailor inflammatory responses. In this Review, we discuss how such information is acquired during phagocytosis and how it is processed to coordinate an immune response.