Little quantitative data exist on the extent of apoptosis (genetically mediated cell deletion) and no data are available on its relation to p53 and bcl-2 expression and on its value as a prognostic factor in NSCLCs. We examined 38 NSCLCs (26 squamous, 8 adeno, 2 adenosquamous and 2 large cell carcinomas) for the frequency of apoptotic bodies by morphometric methods using haematoxylin eosin stained sections and for the bcl-2 and mutant p53 gene product expression using immunohistochemical techniques. We also evaluated the relation of apoptosis, bcl-2 and p53 expression to tumour stage and to each other, Eleven cases were in stage I, 5 were in stage II, 13 were in stage III and 9 were in stage IV. The mean apoptotic count was 9.52 (r: 2-26); 36.8% of cases were positive for bcl-2 and 76.3% of cases were positive for p53 expression. Statistical analysis did not show any correlation between tumour stage and any of the three tested parameters. There was no statistically significant relation between apoptosis and either p53 or bcl-2 expression. There are conflicting reports on the complex relationship between bcl-2, p53 and apoptosis. bcl-2 is suggested to have a prognostic value, independent from stage in SCLCs. Though we did not find any relation between stage and bcl-2 or apoptosis, it remains to be tested whether they have any independent prognostic value in larger series with survival data. Published by Elsevier Science Ireland Ltd.