There have been reports of elevated venom-specific IgE levels in post-mortem sera from patients experiencing fatal Hymenoptera stings so we hypothesized that other cases of sudden death may be due to unrecognized sting anaphyiaxis. Of 94 sera obtained post mortem from subjects who died unexpectedly during the summer months, 22 (23%) contained elevated levels of IgE antibody to at least one insect venom. The causes of death as determined by autopsy did not differ significantly among patients with or without elevated IgE antibody levels. An identical percentage of seropositivity was noted in 48 post-mortem sera from victims of sudden, unexpected death in the winter months. Conversely, only 6% of sera from 92 living blood donors contained elevated venom-specific IgE antibodies. The appreciable incidence of elevated IgE antibodies in the post-mortem groups suggests that sting anaphylaxis should be more highly considered as a possible cause of unexpected death.