The aim of the present study was to evaluate the tumor cell type and sex distribution of patients diagnosed with primary lung cancer during 2004. Patients with primary lung cancer were detected from pathology records. Clinical files of patients were analyzed retrospectively. 1403 patients with primary lung cancer were included in the study. 1238 (88.2%) patients were male and 165 (11.8%) were female and female to male ratio was 1/7.5. When the ratio was compared with 1/10.9 in 1998, the ratio of female patients was determined to increase. Tumor cell type was squamous cell carcinoma in 577 (41.1%) patients, adenocarcinoma in 359 (25.6%), small cell carcinoma in 184 (13.1%), nonsmall cell carcinoma in 115 (8.2%) and other malign tumors in 21 (1.5%) patients. Tumor cell type was not detected in 147 (10.5%) patients. When 147 patients were excluded from the study, the frequency of squamous cell carcinoma was 45.9%, adenocarcinoma was 28.6% and small cell carcinoma was 14.6%. The results of our study show that squamous cell carcinoma is the most frequent tumor cell type in our center and the ratio of female patients is increasing.