Cross neutralization and precipitin tests were performed with coral snake venoms and rabbit antisera against five venoms to determine the most suitable venoms for producing a polyvalent antivenin useful in treating persons bitten by coral snakes. Antisera were produced against Micrurus species M. fulvius, M. frontalis, M. spixii, M. carinicauda, and M. nigrocinctus venom but not against M. mipartitus venom. The latter was the only venom not neutralized by heterologous antisera. M. spixii venom was neutralized by all antisera. Anti-M. frontalis serum neutralized more heterologous (M. spixii) venom than homologous (M. frontalis) venom. The cross reactions suggest that some venom antigens that elicit precipitating and neutralizing antibodies may be distinct. M. frontalis venom produced the most cross-reactive neutralizing antibody, having neutralized five of six venoms. Of the venoms tested, M. frontalis venom would be most suitable for use in the production of a polyvalent coral snake antivenin.