Twenty-four Achatina fulica from Pai-sha of the Pescardores Islands, where no Angiostrogylus cantonensis has been found in A. fulica(4), were inoculated with the first stage larvae of A cantonensis. One snail was killed every day after 24 days following inoculation. The lung of each snail was separated and examined for larvae under microscope. The same lung was then digested with pepsin. The larvae recovered after pepsin digestion were examined for more detailed morphology. This study confirmed that the first stage larvae of A. cantonensis passed through the respiratory pore to the lung of A. fulica and developed into infectious form (3rd stage larvae) in the lung. The second and third stage larvae were found in the lung on the 7th and 17th day respectively after inoculation. Worm capsules were found in the lung on the 12th day after inoculation and the size of capsule was in proportion to the duration of the infection.