The Trying To Quit smoking questionnaire (TTQ), was developed to measure pressure-filled mental states, use of destructive pressure-relief strategies and ambivalent thoughts about quitting smoking among patients with COPD. The aim of this study was to evaluate whether the TTQ (available in an extended and in a reduced version) can be used to predict smoking cessation outcomes in smokers with COPD. As higher TTQ scores indicate higher degree of psychological distress, we hypothesised that TTQ scores at baseline would be negatively correlated with the probability of making a quit attempt, reducing the intensity of smoking and achieving complete abstinence during the 3 months. Smokers with COPD were recruited during planned or unplanned visits to primary healthcare centres, and 109 completed the TTQ at baseline and 85% participated in the follow-up after 3 months. Logistic regression was used to measure the association between the original (19 items) and the brief (14 item) version of TTQ scores and three outcomes: making at least one quit attempt, reducing the intensity of smoking and achieving complete abstinence. In a primary analysis among all the participants higher total score in the original version of TTQ was significantly associated with a lower probability of quit attempts. In a secondary analysis of subgroups of patients classified according to their readiness to quit, high TTQ scores at baseline were associated with lower probability of complete abstinence among patients not ready to quit (adjusted odds ratio (OR)=0.72; 95% confidence interval (CI)=0.53-0.99). Among patients ready to quit, high score on pressure-filled mental states was associated with lower probability of quit attempts (OR=0.78; 95% CI=0.66-0.94) but with higher probability of reduced smoking (OR=1.32; 95% CI=1.05-1.66). Ambivalent thoughts were associated with lower probability of all outcomes, but estimates were not statistically significant. Destructive coping strategies were inconsistently associated with the outcomes. TTQ in its original version and two of its subscales predicted smoking cessation outcomes in the anticipated direction. Therefore, this instrument may be useful in tailoring smoking cessation counselling for patients with COPD.