Dogs, particularly herd dogs, become infected when they consume cysts of the tapeworms in tissues of infected animals (such as sheep, goats, cattle, or pigs). The cysts (called hydatid cysts) develop into adult tapeworms in the dog's intestine. Infected dogs pass tapeworm eggs in their stool.

Unlike many other parasites that dogs can get from exposure to an infected dog’s feces, dogs only become infected with tapeworms by ingesting a flea or rodent carrying a tapeworm. Treatment involves deworming medication, as well as managing flea and rodent exposure.

Dipylidium caninum is a common tapeworm of dogs and cats in the United States and throughout the world. Dogs and cats get Dipylidium tapeworm by swallowing a flea infected with a tapeworm larvae, often while grooming themselves. The larval tapeworm will then develop into an adult tapeworm in the animal's intestine.

Tapeworms of dogs and cats have indirect life cycles with adult tapeworms located in the animals' small intestine and the larval (metacestode) stage found in an intermediate host. Dogs and cats become infected by ingestion of the infected intermediate host. Most urban dogs and cats eat prepared foods and have restricted access to natural prey.