Background: Social differences in mortality have increased in high income countries, but the causes of these changes remain unclear. We quantify the contribution of alcohol and smoking to trends in income differences in life expectancy in 1988-2007 in Finland. Methods: An 11% sample from the population registration data of Finns aged 25 and older linked with an 80% oversample of death records. Alcohol-attributable mortality was based on underlying and contributory causes of death on individual death certificates, and smokingattributable mortality on an indirect method that used lung cancer mortality as an indicator for the impact of smoking on mortality. Results: Alcohol and smoking-attributable deaths reduced life expectancy by about 4.5 years among men. Alcohol-attributable mortality increased and smoking-attributable mortality decreased over the period 1988-2007 leaving the joint contribution stable. Among women the contribution of these risk factors to life-expectancy increased from 0.7 to 1.2 years. In 2003-2007 life expectancy differentials between the lowest and highest income quintile were 11.4 years (men) and 6.3 years (women). In the absence of alcohol and smoking these differences would have been 60% and 36% smaller respectively. Life expectancy differentials increased rapidly over the study period; without alcohol and smoking the increase would have been 69% smaller among men and 85% among women. Conclusions: Alcohol and smoking have a major influence on income differences in mortality and - with the exception of smoking among men - their contribution is increasing. Without alcohol and smoking the increase in life expectancy differentials would have been mostly avoided.