Background: Extensive literature confirms that continued smoking by cancer patients and survivors increases overall mortality, but the benefits of smoking cessation specifically after a cancer diagnosis has not been well described. Methods: Comprehensive evaluation of all Pubmed studies identified using “smoking” and “cancer” published since 2000 was performed to identify all studies with at least 100 patients reporting on the effects of smoking cessation after a cancer diagnosis on overall mortality. Studies that evaluated the exclusive or combined effects of smoking cessation before a cancer diagnosis were not included. Results: Ten (10) studies were identified that met all inclusion criteria including 7 prospective and 3 retrospective studies. The effects of smoking cessation were evaluated for lung cancer patients in 4 studies, head/neck cancer patients in 3 studies, breast cancer patients in 1 study, and multiple cancers in 2 studies. In 3 prospective studies, continued smoking increased risk of overall mortality as compared with never smoking and quitting smoking had an intermediate risk between continued smoking and never smoking. In 7 studies comparing smoking cessation with continued smoking, the median risk of overall mortality in patients who quit smoking was 0.55 (range 0.19-0.92) as compared with continued smoking including 6 of 7 studies with statistically significant reductions in overall mortality risk. Only 1 study reported on overall mortality in cancer patients who were actively enrolled in a smoking cessation program after a cancer diagnosis, and quitting smoking was observed to reduce overall mortality by 44% (HR 0.56, 95% CI 0.36-0.89). Conclusions: Of larger contemporary studies evaluating the effects of smoking cessation after a cancer diagnosis on overall mortality, most demonstrate a significant benefit of quitting smoking.