Nucleolar organizer regions identified by means of an argyrophilic technique (AgNOR) were quantified by digital image analysis in 81 patients with squamous cell carcinoma of the lung. Survival rate was modeled as function of AgNOR expression by Cox regression models controlled for staging, histologic grade, age, and sex. Our results indicate that AgNOR expression has a significant prognostic role. Tumors at lower stages have a lower expression of AgNOR than those with more advanced disease. Tumors with high histopathologic grade have a higher expression of AgNOR. Patients with low AgNOR expression presented a higher survival rate than those with higher amounts of AgNOR. The foregoing results strongly encourage the development of prospective trials to assess the real role of AgNOR in determining prognosis in squamous cell carcinoma of the lung.