SummaryWe have studied a group of twenty‐seven patients who suffer allergic reactions to vespids stings. Specific IgE antibodies to venom extracts fromPolistes gallicusandVespula germanicawere measured by RAST, and the crossreactivity between the two venoms was compared using the RAST inhibition technique. We concluded that, in southern Spain, sensitization toP. gallicuswas more prevalent than that toV. germanica, with 44% of the subjects in this study reacting toP. gallicuscompared with 33% toV. germanica.However, there was a considerable degree of crossreactivity between the two species. It is evident thatPolistesis an important species in this area; however, both in Spain and other Mediterranean countries,V. germanicavenom is used almost exclusively for diagnosis and immunotherap