The cell-surface hydrocarbon chains have an important role to characterize cells, however, the information for polyploid cells is little. To assess the expression of sugar chain in cells polyploidized by different mechanisms, the lectin binding was examined. Meth-A cells, a methylcholanthrene-induced mouse abdominal dropsy sarcoma cell line, were polyploidized by demecolcine and K-252a, stained with the FITC labeled lectins, wheat germ agglutinin (WGA), Ricinus cornmunis agglutinin I (RCA120), peanut agglutinin (PNA) and Ulex europeaus agglutinin I (UEA-I), and measured for their fluorescence by flow cytometry. The WGA and UEAI bindings increased proportionally to the area of cell surface, not but to the DNA content. The RCA120 and PNA bindings were significantly larger in K-252a-induced polyploid Meth-A cells than in demecolcine-induced ones. The lectin binding in the diploid cells was almost the same, regardless the presence and the absence of the 2 polyploidizing agents. The lectin binding was roughly proportional to the cell-surface area of polyploidized Meth-A cells and it was affected by the polyploidizing methods.