As more people begin to survive first cancers, there is an increased need for science-based recommendations to improve survivorship. For survivors of head and neck cancer, use of tobacco and alcohol before diagnosis predicts poorer survival; however, the role of continuing these behaviors after diagnosis on mortality is less clear, especially for more moderate alcohol consumption. Patients (n = 264) who were recent survivors of early stage head and neck cancer were asked to retrospectively report their tobacco and alcohol histories (before diagnosis), with information prospectively updated annually thereafter. Patients were followed for an average of 4.2 years, with 62 deaths observed. Smoking history before diagnosis dose-dependently increased the risk of dying; risks reached 5.4 [95% confidence interval (95% CI), 0.7-40.1] among those with >60 pack-years of smoking. Likewise, alcohol history before diagnosis dose-dependently increased mortality risk; risks reached 4.9 (95% CI, 1.5-16.3) for persons who drank >5 drinks/d, an effect explained by beer and liquor consumption. After adjusting for prediagnosis exposures, continued drinking (average of 2.3 drinks/d) postdiagnosis significantly increased risk (relative risk for continued drinking versus no drinking, 2.7; 95% CI, 1.2-6.1), whereas continued smoking was associated with nonsignificantly higher risk (relative risk for continued smoking versus no smoking, 1.8; 95% CI, 0.9-3.9). Continued drinking of alcoholic beverages after an initial diagnosis of head and neck cancer adversely affects survival; cessation efforts should be incorporated into survivorship care of these patients.