Background: Continued smoking after a cancer diagnosis is associated with poorer outcomes. Tobacco retail availability is negatively associated with cessation in non-cancer patients (pts), but has not been explored in cancer survivors. We evaluated the impact of tobacco retail availability on cessation in lung and HN cancer pts. Methods: Lung and HN cancer pts (Princess Margaret Cancer Centre, Toronto) completed questionnaires evaluating changes in tobacco use with a median of 26 months apart. Validated tobacco retail location data were obtained from Ministry of Health and pt home addresses were geocoded using ArcGIS 10.6.1, which calculated walking time/distance to nearest vendor, and vendor density within 250 meters (m) and 500m from pts. Multivariable logistic regression and Cox proportional hazard models evaluated the impact of vendor availability on cessation and time to quitting after diagnosis respectively, adjusting for significant clinico-demographic and tobacco covariates. Results: 242/721 lung and 149/445 HN pts smoked at diagnosis; subsequent overall quit rates were 66% and 49% respectively. Mean distance and walking time to a vendor was 1 km (range 0-13) and 11 min (range 0-156). On average, there was one vendor (range 0-19) within 250m and four vendors (range 0-40) within 500m from pts; 37% and 61% of pts lived within 250m and 500m from at least one vendor respectively. Greater distance (aOR 1.18 per 1000m [95% CI 1.00-1.38] p = 0.05) and increased walking time (aOR 1.01 per minute [1.00-1.02] p = 0.05) were associated with quitting at one year. Living within 250m (aOR 0.52 [0.32-0.84] p = 0.008) or 500m (aOR 0.57 [0.35-0.92] p = 0.02) to at least one vendor reduced quitting at one year. Living near more vendors within 500m had an increasing dose effect on reducing cessation rates at one year (aOR 0.96 per vendor [0.93-1.00] p = 0.05). Living within 500m to a vendor reduced chance of quitting at any time (aHR 0.66 [0.48-0.91] p = 0.01). HN and lung subgroups revealed similar associations. Conclusions: Close access to tobacco retail outlets is associated with reduced cessation rates for lung and HN cancer survivors. Reducing density of tobacco vendors is a cessation strategy that can positively impact cancer pt outcomes.