A solid-phase radioimmunoassay (SPRA) has been developed to measure IgG antibodies to bee venom (BV) and phospholipiase A2 (PLA) in human sera. The principle of the test is similar to that of the radioallergosorbent test (RAST) measuring IgE antibody. Cyanogen-bromide-activated paper discs coupled with BV or PLA followed by supplementary coupling with human serum albumin were incubated with standard or test sera, washed, and incubated with 125I-labeled anti IgG. The serum levels of the IgG antibody have been temporarily expressed in arbitrary units. the reaction between the antigen and antibody was specific and the results were reproducible. Sera from 19 beekeepers, 42 beesting-sensitive patients and 20 blood donors (controls) were assayed by the SPRA. IgG antibodies to BV and PLA could not be detected (less than 4 U/ml) in all control sera, in 25 of the 42 patients and in one beekeeper. The IgG antibodies in 17 patients ranged between 5 to 58 U/ml (mean 7.6 U/ml), and in the 18 beekeepers ranged between 8 to 160 U/ml (mean 59 U/ml).