The aim of this study was to estimate the diagnostic and prognostic significance of carcinoembryonic antigen (CEA), beta(2) -microglobulin (beta(2)-MG), and calcitonin (CAL) as tumor markers in patients with lung cancer. Thirty patients were included and CEA, beta(2)-MG, and CAL serum levels were measured before treatment, one month and six months after treatment. Results taken showed that CEA mean base line level was 23,4 ng/ml, elevated in 80% of small cell lung cancer (SCLC) cases, in 93% of adenocarcinoma, in 84% of squamous cell type carcinomas, and in 84% of large cell type carcinomas. The mean beta(2)-MG level was 3,6 mg/lt, elevated in 70% of SCLC, in 40% of adenocarcinoma, in 66% of large cell and in 50% of squamous cell type carcinomas. The mean CAL level was 170 pg/ ml, elevated in 60% of SCLC, in 33% of adenocarcinoma, in 16% of large cell and in 16% of squamous cell type carcinomas. In conclusion, CEA, beta(2)-MG, and CAL, in a whole view, can be used as tumor markers with diagnostic and prognostic value in bronchogenic cancer.