The ability of mononuclear blood cells (PBMC), derived from patients with cancer of the larynx, to produce IFN-gamma in vitro was assessed in this paper. Thirty patients (27 male, 3 female) were qualified to the study. Their mean age was 65 (range: 41 to 78 years), tumour sizes found in the group were from T2 to T4, levels of pathologic malignancy G2 or G3. The percentage rates different blood cells phenotypes (CD3+, CD3+ HLADR+, CD4+, CD8+, CD14+ HLADR+, CD19+, CD56+) were evaluated by means of flow cytometry (Coulter EPICS XL). The control group consisted of 20 healthy blood donors. PBMC were derived by centrifugation of heparinized venous blood on Lymphoprep gradient according to Boyum method. Double cell cultures were performed for 24 hours with antibody anti-CD3 or recombinant interleukins 12 (rhIL-12) or 18 (rhIL-18). The statistic analysis was based on Student t and Mann-Whitney's test with significancy at p<0.05. A significant decrease in the production of IFN-gamma by PBMC in patients with laryngeal cancer after stimulation with antiCD3 (p=0.018), rhIL-12 (p=0.027), rhIL-18 (p=0.016) was found in comparison with the controls. The results suggest a decreased production of IFN-gamma in patients with cancer of the larynx.