In 1984, over 10,000 refugees left the Indonesian province of Irian Jaya, and thus possibly imported Taenia solium taeniasis/cysticercosis into Papua New Guinea, which was believed to be free of T. solium until 1966. In a serological survey carried out in 1986, 50 refugees originating from areas endemic for T. solium and 171 patients from other areas with symptoms suggesting the possibility of cysticercosis were examined. As a sensitive prescreening technique an ELISA was used with a crude antigen extract obtained from T. solium metacestodes of pig origin. Of 221 persons investigated, 79 (36%) were positive in ELISA. For excluding frequently occurring cross-reactions in ELISA, Western-blotting (or EITB, enzyme-linked immunoelectrotransfer blot) was employed. In this test the demonstration of antibody activity to the 26 or the 8 kilodalton band has been proved to be species-specific for T. solium cysticercosis. One from 79 patients positive in ELISA was simultaneously positive (26 and 8 kDa) in Western blot, corresponding to the first case found in Papua New Guinea with a highly probable T. solium cysticercosis. This patient, originating from an endemic area in Irian Jaya, had immigrated into Papua New Guinea in 1980. The present work emphasizes the need for using highly specific immunodiagnostic techniques in seroepidemiology of larval cestode infections. T. solium taeniasis/cysticercosis remains a risk for Papua New Guinea, and refugees originating from endemic areas should be regarded as potential carriers of T. solium.