This study reports the evaluation of SCC-Ag in 58 patients with squamous cell carcinoma of the oral mucosa. Serum samples were obtained prior to treatment and 10-14 days after. SCC-Ag levels were determinated by microenzymatic kit IMx Abbot Laboratories. Elevation of antigen levels were found in 60,3% (100% for T₄, 54,5% for T₃). SCC-Ag level was statistically significant in tumours T₂ and T₃. Patients with previously elevated pretreatment values normalized after surgery. Early metastasising or local recurence of the tumour were related to high posttreatment values of SCC-SAAg.