Genetic and environmental factors (dietary and smoking) influence lung cancer epidemiology and induce epigenetic modifications that should be assessed in individual populations. We analyzed p16 methylation among Greek non-small cell lung carcinoma patients and smokers using two-stage methylation-specific polymerase chain reaction. One hundred and fifty specimens from cancerous and adjacent non-cancerous tissue, bronchial washings and sputum from patients and 48 specimens, mostly sputum, from disease-free smokers were included. p16 methylation was very frequent in biopsies (82.85%) and bronchial washings (non-small cell lung carcinoma, 80.35%; small cell lung carcinoma, 16.66%) from patients, but also in adjacent non-cancerous tissue (45.71%). Concordance of p16 methylation and positivity by cytological examination was 51.78%. Methylation was also observed in sputum from asymptomatic cytology-negative smokers (22.5%) and chronic obstructive pulmonary disease patients (three of eight). Among disease-free individuals, methylation correlated only with heavy smoking (>50 pack-years, P<0.001) and differed among male and female disease-free smokers. In summary, p16 methylation is very frequent among non-small cell lung carcinoma patients, and correlates with heavy cigarette consumption only in disease-free smokers.