We report seven cases of false-positive Plasmodium falciparum histidine-rich protein 2 (PfHRP2) malaria assay results in patients with acute schistosomiasis caused by Schistosoma mekongi. PfHRP2 assays were negative in travelers infected with Schistosoma mansoni or Schistosoma haematobium (n = 13). Malaria was ruled out and rheumatoid factor was negative in all patients.