OBJECTIVE: This study examines the intensity of expression of β1, α2, α3, α5, α6 integrin subunits in oral squamous cell carcinoma (SCC) as opposed to normal oral epithelium, and the intensity of expression and distribution pattern of the above subunits in relation to tumour differentiation grade. MATERIALS AND METHODS: Cryostat sections of 25 cases of oral SCC and 15 cases of normal oral epithelium were studied by immunohistochemistry (APAAP method). RESULTS: The intensity of expression of β1, α2 (Pearson χ2P < 0.001) and α6 (Test for Trend P < 0.05) integrin subunits was reduced significantly in SCC compared to normal oral epithelium. All integrin subunits were mainly expressed in the peripheral cell layer of tumour islandS. No correlation was found between the intensity of integrin expression and the degree of differentiation in SCC. The same applied to the distribution pattern of the integrin subunitS. By means of cross examination of all integrins, the loss of intensity of α2β1 integrin expression was found to have the strongest correlation with oral SCC (Ordered Logistic Regression). CONCLUSIONS: Reduced intensity of expression of all subunits was found in oral SCC compared to normal epithelium. Further investigation is needed to determine whether α2β1 integrin expression can be used as a prognostic evaluator for the behaviour of the disease.