Fibronectin (FN) is a multifunctional adhesive glycoprotein that exists in the extracellular matrix and body fluids. As a result of alternative splicing, extra segments (ED-A and ED-B) may be included in the fibronectin molecule. These isoforms of FN, together with FN that has an extra glycosylation (OFFN), are strongly associated with a number of tumours, including oral squamous cell carcinoma (SCC). In view of the likely exfoliation of these cells into the oral cavity from tumours, OFFN might be present in saliva. As such, the presence of OFFN in saliva may be an indicator of oral SCC. The saliva of 12 patients with oral squamous carcinoma and 8 disease-free individuals was measured for OFFN using an enzyme-linked immunoassay. Salivary OFFN levels were similar for patients both with oral SCC and those without, suggesting that this would not be a useful test for the detection of oral SCC.