Abstract: In view of the fact that the schistosomicidal activity of lucanthone and UK 3883 has been markedly enhanced by methanolization, niridazolylmethanol and its esters were synthesized through esterification of niridazolylmethanol with acyl chlorides or anhydrides of appropriate acids. Most of the esters were shown to possess pronounced antischistosomal activity in mice infected with Schistosomasis japonica. The structureactivity relationship was discussed.