When Small-Ear-Miniature pigs subcutaneously injected once with frozen oncospheres of Taiwan Taenia, Korea Taenia, T. saginata or T. solium emulsified with Freund's complete adjuvant (1·6 × 104/0·4 ml) were challenged orally with 1·6 × 104 viable eggs of Taiwan Taenia 41 days later, they all showed strong resistance compared with pigs vaccinated with T. solium. Most pigs (5/8) of the former 3 groups harboured no cysticerci. The number of cysticerci was 5·5±9·1 (mean±S.D.), whereas pigs of the T. solium group and control group harboured 160±30·1 and 661±637·2 cysticerci, respectively. All cysticerci recovered from vaccinated pigs and most cysticerci in control pigs were degenerated or calcified at 36–55 days after oral egg challenge. These results strongly suggest that oncospheres of Taiwan Taenia and Korea Taenia are very similar to T. saginata in their immunogenicity in pigs.