Mouse models of systemic anaphylaxis are important tools for the study of mast cell function, for the elucidation of the pathomechanisms of anaphylaxis, and for identifying and characterizing potential therapies for anaphylaxis. Here, we describe two murine models of systemic anaphylaxis that have been a key part of research in these areas. In a passive model, mice are sensitized with antigen-specific IgE antibody 24 h prior to antigen challenge. In an active model, mice are instead sensitized with antigen 18-21 days prior to challenge. Hypothermia serves as the primary quantifiable indicator of anaphylaxis in these models.