The detection of antibodies against keyhole limpet haemocyanin (KLH) (extracted from Megathura crenulata ) has been described as a reliable tool for serological diagnosis of acute, but not chronic, schistosomiasis. We evaluated the immunoglobulin (Ig) G and IgM anti-KLH enzyme-linked immunosorbent assay (ELISA) for the serological diagnosis of light schistosome infections and to follow response after treatment, using sera from a group of Dutch travellers returning from Mali with acute schistosomiasis. Before chemotherapy, the sensitivities of the anti-KLH IgM and IgG <scp>elisas</scp> were 74% and 63%, respectively. In contrast, a sensitivity of 100% was found with an immunofluorescence assay for determination of IgM antibodies against gut-associated glycoconjugates. There was no significant difference in the anti-KLH response before, and one year after, therapy. These results indicate that, for travellers from non-endemic areas like The Netherlands with generally light schistosome infections, detection of antibody response against KLH is not a useful tool for serodiagnosis of acute schistosomiasis.