Fifty-nine beekeepers who had been practicing apiculture for more than 2 years were selected in order to determine the distribution of bee venom specific IgG subclasses using ELISA. The assays were standardized into arbitrary units. For comparison, IgG subclasses were determined in eight individuals allergic to bee stings who did not receive specific treatment. No correlation was detected between beekeeping time and specific IgG1, IgG2 or IgG4 levels. There was a correlation between IgG2 levels and mean number of stings per month received by the beekeepers. Twenty-five percent of the beekeepers presented bee venom specific IgE class II or more in an ELISA assay. The IgG1 levels detected in beekeepers were similar to those detected in allergic individuals. IgG2 and IgG4 levels were significantly higher in beekeepers than in allergic individuals. IgG3 was not detected in any group studied. In conclusion, the maintenance of high levels of bee venom specific IgG2 and IgG4 represents a characteristic of beekeepers. These subclasses may be related to a modulatory effect of IgG on allergic reactions.