The major chemical components in the venom of red imported fire ants, Solenopsis invicta Buren, are 2-methyl-6-alkyl or alkenyl piperidines. After isolating the extracts of poison glands and whole worker bodies with column chromatography, we obtained fractions containing a mixture of six piperideine alkaloids. Reduction of those samples using NaBH(4) in ethanol generated piperidine alkaloids found in the fire ant poison gland, resulting in both the cis- and the trans-piperidine alkaloids. The mass spectra and gas chromatographic behavior of most piperidine alkaloids from fire ant venom have been well-characterized, which significantly facilitated the identification of these piperdeine compounds. On the basis of the mass spectra and profiles of NaBH(4) reduction products, we identified these alkaloids as 2-methyl-6-tridecenyl-6-piperideine, 2-methyl-6-tridecyl-6-piperideine, 2-methyl-6-pentadecenyl-6-piperideine, 2-methyl-6-pentadecyl-6-piperideine, 2-methyl-6-heptadecenyl-6-piperideine, and 2-methyl-6-heptadecyl-6-piperideine. To our knowledge, this is the first time that these piperideine alkaloids have been reported in red imported fire ant poison glands.