Integrin-mediated drug resistance is based on the adherence of cells to extracellular matrix proteins through integrins. In human laryngeal carcinoma cells a mechanism of multidrug resistance mediated by αvβ3 integrin have been described. In the present study we investigated whether similar mechanism exists in tongue squamous carcinoma cells (Cal27) which express a small amount of αvβ3 integrins, and Cal27-derived stable transfectants with increased expression of αvβ3 integrin. The cell clones were produced by stable transfection of Cal27 cells with a plasmid expressing the β3 subunit. In one stable transfectant the expression of αvβ3 was increased but the expression of αvβ5 remained the same in comparison to parental cell line. The other stably transfected cell line showed an increase in αvβ3 expression and a moderate decrease in αvβ5 expression, due to the competition of β3 for available αv in the cell. The sensitivity of Cal27 and Cal27-derived αvβ3 integrin expressing clones to anti cancer drugs was determined using MTT assay. Our results showed that both Cal27-derived αvβ3 integrin expressing cell lines were resistant to cisplatin, doxorubicin and mitomycine C. This thesis shows that increased αvβ3 integrin expression can protect cells from various citostatics. Thus measuring the expression of αvβ3 integrin in head and neck cancer cells could be an important indicator of tumor resistance to anti-cancer drugs.