[Objective] To obtain the genetic information on Necator americanus and to search for the purpose genes.[Methods] Mrna was isolated from the third stage larvae of Necator americanus maintained in hamsters.Double strand Cdna was synthesized and ligated to ΛzapⅡ vector to construct the Cdna library.Expresed se-quence tages (ESTs) were obtained by single pass sequencing of randomly isolated Cdna clones from the es-tablished library.[Results] A Cdna librazy of N.americanus was successfully constructed with high recombi-nant efficiency.The titer of unamplified library was 1×107.The insert size was about 750～3000bp.Of 11 ESTs obtained from the library,7 have a significant homology with certain functional genes.[Conclunsion]A high quality and high representative Cdna library of N.americanus was constructed at the first time and ome functional genes were identified from the library by ESTs.