Infections with filarial nematodes are well documented in numerous orders of birds worldwide. The filarial nematode Paronchocerca ciconarum has been found within the heart and pulmonary vessels of saddle-billed storks (Ephippiorhynchus senegalensis), as well as other species of African storks. Until now, identification of microfilariae on direct smears of circulating blood has been the only antemortem method reported to successfully diagnose cardiovascular filarial infections in birds. We report the use of a commercial test kit for canine heartworm (Dirofilaria immitis) antigen to aid in detecting adult P ciconarum infection in 2 saddle-billed storks, 1 at necropsy and 1 antemortem. Results of this test were positive for both birds. Direct blood smears and blood filtration tests were also used to identify circulating microfilariae. Both birds died because of separate, unrelated causes but had adult P ciconarum filariae in the pulmonary arteries and, in 1 stork, the right ventricle. On the basis of our findings in these 2 storks, testing for canine heartworm antigen, in conjunction with a blood filtration test and stained blood smear of peripheral blood, may improve detection of cardiovascular filarial infections in birds.