WD40-repeat proteins have four to eight repeat units, which have Gly-His (GH) and Trp-Asp (WD) at both termini and fold into a beta-propeller. In particular, the WD40-repeat protein of Clonorchis sinensis (CsWD1) has seven WD-repeat units and is expressed stage-specifically in metacercariae. By yeast two-hybrid screening, putative interacting protein cDNAs were cloned from a C. sinensis metacercaria cDNA library and purified further by higher stringency screening and lacZ colony-lift assay. After assessing their nucleotide and polypeptide sequences, 21 putative partner protein cDNAs were selected and assembled into 14 clones. Using YRG2 strain yeast, 12 putative partner protein clones were confirmed to interact with CsWD1 protein. These 12 proteins were grouped into functional categories, i.e., signal proteins, transporters, proteases, and muscle proteins. These results suggest that CsWD1 protein is associated with intracellular protein translocation and cell cycle control in C. sinensis metacercaria.