Dogs infected with Angiostrongylus vasorum, a potentially lethal parasite parasitizing the heart and pulmonary arteries, may present severe respiratory, haematological and neurological signs. In this first large-scale seroepidemiological survey, 4003 sera originating from Germany and 4030 from the UK were tested by an ELISA for the detection of circulating antigen of A. vasorum, and by a separate ELISA detecting specific antibodies. In Germany, where mainly western federal states were sampled, 0.3% (n = 13, CI: 0-2-0.6%) of dogs were positive in both ELISAs, whereas in total 0.5% (n = 20, CI: 0.3-0.8%) were antigen-positive and 2.25% (n = 90, CI: 1.8-2.8%) were positive for specific antibodies. Regions with antigen-and antibody-positive animals were overlapping. In the UK, where mainly the south of the country was sampled, 0.97% (n = 39, CI: 0.7-1.3%) of dogs were antigen-and antibody positive. In total, 1.32% (n = 53, CI: 1.0-1.7%) were antigen-positive, and 3.2% (n = 129, CI: 2.7-3.8%) were positive for specific antibodies, again in overlapping regions. These results confirm the occurrence of A. vasorum in a random dog population originating from large parts of the countries investigated. The use of the tests alone or in combination was considered as a function of their sensitivities and specificities, in order to guide efficient clinical and epidemiological application.