The effect of 4-weekly anthelmintic dosing and other treatment regimes on the serological response of dogs toTaenia oviswas examined. Most dogs which were frequently fed infected meat and dosed with a cestocidal anthelmintic at 4-week intervals eventually showed a positive ELISA absorbance. The absence of dosing, or intermittent dosing, of repeatedly infected dogs raised ELISA absorbances to very high levels in most dogs and these absorbances took an increasingly longer time to fall after each new infection. The feeding of large numbers of frozen, dead cysts to sensitised dogs raised absorbance levels. The serological test forT. ovisinfections in dogs does not detect false postives. Positive tests result from the dog being exposed toT. ovisscolex secretory antigen.