Migration and distribution of Ancylostoma caninum larvae in the tissues of mice orally infected with 1000 larvae, and establishment of patent infection from the mice to the definitive host, were studied. Larval yield from different organs of mice, after digestion with artificial gastric juice, indicated that the highest recovery was at 4 h post-infection (62.8%), and thereafter a slight decline occurred up until 30 days post-infection (51.5%). Migration of larvae to the lungs occurred within 4 h, to the liver within 12 h and into the heart within 24 h. No larvae were recovered from spleen and kidney tissues. From the 9th day onwards larvae were also recovered from the brain. Migration in the muscles of head and neck occurred within 4 h, in the thoracic and abdominal muscles at 24 h and in lumbosacral and leg muscles at 48 h. The establishment of patent infections in the definitive host was studied by feeding the orally- and percutaneously-infected mice to hookworm-free pups at 10 and 30 days post-infection. The mean necropsy worm burden in the pups fed with the orally-infected mice was comparatively higher than in the pups fed cutaneously-infected mice.