Sociological research on medical discussions of lifestyle suggests that smoking patients may be seen as knowingly causing their medical problems. Therefore, it may be interactionally problematic for doctors to raise the issue of smoking cessation in relation to patients’ serious health problems. While a serious illness can be expected to bring to the fore the relevance of smoking cessation advice, it may also give rise to questions about patients’ right to treatment. This study uses conversation analysis to explicate how patients and doctors manage issues of responsibility in smoking cessation discussions in the face of a serious medical problem that strongly correlates with smoking. The findings show that whilst ill health can be referred to in a confrontational manner, it can also give smoking cessation a ‘now or never’ status that downplays patients’ responsibility for not having quit before. Based on these findings, the paper concludes that for warranting further smoking cessation advice, how doctors and patients verbalise the link between smoking and a serious medical problem matters more than whether they do so.