Background: In general, smoking increases the risk of mortality. However, it is unclear which specific cause of death carries the highest risk. Moreover, the impact of changes in smoking habits throughout life on mortality is less studied. Methods: We studied the impact of baseline and lifetime smoking habits, duration of smoking and duration of smoking cessation on the risk of all-cause mortality, mortality of cardiovascular diseases (CVD), and mortality of any cancer and lung, colorectal, prostate, and breast cancer, in a large cohort study (Vlagtwedde-Vlaardingen 1965-1990, with follow-up on mortality until 2009, n = 8,645). We used Cox regression models adjusted for age, BMI, sex, and place of residence. To determine which cause of death carried the highest risk we performed competing-risk analyses on mortality due to cancer, CVD and other causes. Results: Current light, moderate, and heavy cigarette smokers, and lifetime persistent smokers had a higher risk of all-cause, CVD, any cancer, and lung cancer mortality compared to never smokers. A longer duration of smoking associated with a higher risk of any and lung cancer [HR (95% CI) = 1.03 (1.00-1.06) and 1.10 (1.03-1.17) respectively], but not with other mortality causes. A longer duration of smoking cessation associated with a lower risk of all-cause and any cancer mortality. The competing risk analyses showed that ex- and current smokers had a higher risk of both cancer and CVD mortality compared to all other mortality causes. In addition, heavy smokers had a higher risk for cancer mortality compared to CVD. Conclusions: Our findings emphasize on the importance of smoking-related competing risks when studying the smoking-related cancer mortality in a general-population and that smoking cessation effectively reduces the risk of all-cause and any cancer mortality.