We assessed the usefulness of serologic testing in monitoring strongyloidiasis in immigrants after treatment with two doses of ivermectin. An observational study was conducted in a group of Cambodian immigrants residing in Melbourne who were treated for strongyloidiasis and followed-up in a general practice setting. Two doses of ivermectin (200 μg/kg) were administered orally. Periodic serologic enzyme-linked immunosorbent assay testing was undertaken for up to 30 months after treatment. Antibody titers for Strongyloides sp. decreased in 95% (38 of 40) of the patients, 47.5% (19 of 40) had a decrease in optical density to less than 0.5, and 65% (26 of 40) reached levels consistent with a cure during the follow-up period. Serologic testing for Strongyloides sp. is a useful tool for monitoring a decrease in antibody levels after effective treatment. This testing should be carried out 6–12 months after treatment to ensure a sustained downward trend suggestive of cure.