To study the changes in carbohydrate expression associated with the progression of malignant phenotype, we have used the series of human urinary bladder epithelial cell lines. Non-tumorigenic and non-invasive cell lines, with infinite life span, were defined as transformation grade II (TGr II). Cell lines producing tumors in nude mice and invading fragments of embryonic chick hearts in vitro were defined as TGr III. In the present review the results obtained from our immunochemical, biochemical and structural studies on glycosphingolipids and glycoproteins of 10 human urothelial cell lines representing both grades of transformation are summarized and discussed in relation to the literature data. TGr III cell lines are characterized by decreased level of the GM2 ganglioside, presence of sialyl-Le(a) ganglioside, increased amount of more highly branched, tri- and tetraantennary N-acetyllactosamine-type glycans and higher number of binding sites for peanut lectin and wheat germ agglutinin lectin, as compared to non-tumorigenic and non-invasive TGr II cell lines.