A soluble somatic preparation (SSP) of adult Dipetalonema viteae was prepared. Aliquots of the aqueous insoluble debris (cuticles and membranes) left after the extraction of SSP were solubilized separately with Triton X-100 and lithium diiodosalicylate to yield a Triton solubilized preparation (TSP) and lithium diiodosalicylate solubilized preparation (LSP), respectively. SSP was sequentially chromatographed on a series of Sephadex columns, G50; then fraction 1 from G50 on G100 and finally fraction 1 from G100 on G200 yielding 5, 4, and 5 fractions on G50, G100, and G200, respectively. TSP and LSP were each sequentially chromatographed on Sephadex G50 and G200 to yield 5 and 4 fractions for TSP and 6 and 3 fractions for LSP, respectively. Each Sephadex fraction from each separation was further resolved by polyacrylamide gel electrophoresis (PAGE). Immunodiffusion studies with a rabbit antiserum to SSP gave 4 precipitin bands with SSP, 1 with TSP, and none with LSP. The single precipitin arc produced with TSP showed partial identity with an SSP arc. Disc immunoelectrophoresis allowed the identification of the proteins separated by PAGE, which precipitated with the rabbit anti-SSP serum.