Inflammation is the coordinated immune response to harmful stimuli that appear during infections or after tissue damage. Cells of the innate immune system are the central players in mediating inflammatory tissue responses. These cells are equipped with an array of signaling receptors that detect foreign molecular substances or altered endogenous molecules that appear under situations of stress. This review provides an overview of recent progress in elucidating the molecular mechanisms that lead to inflammatory reactions. We discuss the current knowledge of the mechanisms leading to the activation of cytoplasmic, multimolecular protein complexes, termed "inflammasomes," which regulate the activity of caspase-1 and the maturation and release of IL-1beta.