This study examined the suitability of immunoblot assays using antigen B from hydatid cyst fluid (HCF) and the recombinant protein EpC1 to estimate the prevalence of hydatid infection in threatened small macropodid populations. When HCF antigen B was used on sera from 29 wild eastern grey kangaroos (Macropus giganteus) examined for the presence of hydatid cysts at necropsy (17 positive and 12 negative), and from five captivebred macropodids, the sensitivity and specificity were 88% and 41%, respectively. Following optimization, the use of rEpC1 on sera from 51 wild eastern grey kangaroos (48 positive and 3 negative at necropsy), and from 9 captive bred macropodids, resulted in sensitivity and specificity of 48% and 92% respectively.