Study have infected successfully 10/10 chickens with Raillietina spp. in Thainguyen (Vietnam) in 2010. Raillietina completes its cycle for 22 - 25 days. Chickens which were infected with Raillietina spp. have passed out proglotoids to stools continuously since the tapeworm completed its cycle. 2/10 of experimental chickens manifested the apparent clinical signs: emaciation, depression pale crests and combs, watery stools with a lot of prognostics, thirst. There were 8 - 67 tapeworms in infected chickens. The cestode lived mainly in small intestine (accounting for 90,58 percent of total parasitic tapeworms). There were 2 chickens showing apparent lesion: catarrhal enteritis with a lot of petechia, pinkish intestinal fluid, There were scolex anchoring to intestinal mucosa.