Abstract The proinflammatory cytokine IL-1β plays an important role in antifungal immunity; however, the mechanisms by which fungal pathogens trigger IL-1β secretion are unclear. In this study we show that infection with Candida albicans is sensed by the Nlrp3 inflammasome, resulting in the subsequent release of IL-1β. The ability of C. albicans to switch from a unicellular yeast form into a filamentous form is essential for activation of the Nlrp3 inflammasome, as C. albicans mutants incapable of forming hyphae were defective in their ability to induce macrophage IL- 1β secretion. Nlrp3-deficient mice also demonstrated increased susceptibility to infection with C. albicans, which is consistent with a key role for Nlrp3 in innate immune responses to the pathogen C. albicans.