This study examines the production and persistence of peripheral lymphedema in ferrets experimentally infected with Brugia malayi. In 14 of 18 ferrets inoculated 2 or more times with infective larvae, lymphedema developed in the inoculated paw or paw and lower leg. In 5 of these ferrets lymphedema had persisted for 8 to 18 months at the time of necropsy. Lymphedema rarely was observed following a single inoculation of larvae or in microfilaremic ferrets. The results suggest that the ferret may be a useful experimental animal for the study of chronic lymphostatic disorders in filariasis.