Introduction: Our aim was to investigate changes in smoking prevalence, smoking cessation support and factors associated with successful smoking cessation in patients with asthma and COPD. Methods: Questionnaires about available smoking cessation resources were completed by 54 primary health-care centers and 14 hospitals in central Sweden in 2005 and 2012. Patient data were collected using record reviews and patients questionnaires for two cohorts of randomly selected asthma and COPD patients in 2005 (n = 2306; with a follow up in 2012), and in 2014/2015 (n = 2620). Smoking prevalence, available individual and group smoking cessation support, and factors associated with successful smoking cessation were explored. Results: Smoking prevalence decreased from 11% to 6% (p < 0.0001) in patients with asthma but was almost unchanged in patients with COPD (28 to 26%, p = 0.37). Smoking cessation support increased from 53% to 74% (p = 0.01). A high cardiovascular risk factor level, including diabetes mellitus and hypertension was associated with improved smoking cessation in patients with asthma (OR (95% CI) 3.87 (1.04–14.4), p = 0.04). A higher magnitude success was observed in men with asthma (OR (95% CI) 27.9 (1.73–449), p = 0.02). More highly educated women with asthma had successful greater smoking cessation (4.76 (1.22–18.7), p = 0.04). No significant associations were found in COPD. Conclusions: The smoking prevalence in patients with asthma but not in COPD has almost halved in Sweden during a 7-year period. The availability of smoking cessation support has increased. Suggested factors related to successful smoking cessation are higher level of education in women with asthma and cardiovascular risk factors in men and women with asthma.