In order to overcome the false negative diagnosis of infection with C. philippinesis at time of absence of eggs in stool, coproantigen prepared from stools of infected patients was evaluated serologically. This antigen was able to detect anti-Capillaria antibodies in the sera of infected cases at the same OD level produced with Capillaria crude worm antigen using indirect ELISA technique C. philippenensis coproantigen did not cross-react with sera from patients with schistosomiasis mansoni, fascioliasis or strongyloidiasis at 1:00 serum dilution. Laboratory-prepared hyperimmune sera versus crude worm antigen of C. philippinensis succeeded in capturing Capillaria antigen prepared from the stools of infected patients and did not cross react with coproantigens prepared from stool samples of cases infected with S. mansoni or Fasciola using sandwich ELISA technique.