The aim of our study was the assessment of the ploidia and its influence on the remission time and the survival of surgically treated patients with squamous cell lung cancer. The results were then related to the clinical staging, grading, size and localization of the tumor. The tissue samples (n = 60) of squamous cell lung carcinoma resected between 1995-1996 at the Department of Thoracic Surgery at University of Medical Sciences in Poznań were prepared using modified Hedley's method. The measurement was done in Cytoron Absolute flow cytometer. The abnormal DNA (aneuploid) was found in 40% of tumors. In two-year observation period more patients died with aneuploid tumors (54.6% deaths) than with diploid tumors (35.2% deaths). No significant correlation was found between the ploidy and frequency of metastasis to regional lymph nodes, tumor size, localization and grading. The estimation of the DNA content in the cancer cells seems to be a significant and valuable prognostic factor. The measurement of the DNA content can be useful in patients to estimate risk of recurrence after surgery.