Abstract Background Cardiovascular disease (CVD) and cancer mortality rates in Eastern European countries are among the highest in the world. Although unhealthy diet is an important risk factor for both of these chronic diseases, traditional eating habits and their health effects in this region have not yet been explored. This analysis assessed the relationship between traditional dietary pattern and mortality from all-causes, CVD and cancer in Eastern European population-based cohorts. Methods We used data from the Health, Alcohol and Psychosocial factors in Eastern Europe (HAPIEE) multi-centre prospective cohort study based in Russia, Poland and the Czech Republic (age range at baseline: 45-70 years). Diet was assessed by food frequency questionnaire, and we constructed an Eastern European diet score (EEDS) from nine food groups considered as “traditional” in this region. The relationship between EEDS and all-cause, CVD and cancer mortality was calculated with Cox-regression models. Results From the 18,852 participants, 2,234 died during the average follow-up of 11.7 years. In multivariable adjusted models, participants with high adherence to the traditional Eastern European diet had significantly higher risk of all-cause (HR 1.20; 95% CI 1.05-1.38) and CVD deaths (1.32; 1.05-1.64) compared to those with low adherence. The association with cancer mortality was not significant (1.12; 0.90-1.40). From the specific EEDS components, high consumption of lard was significantly positively related to all three mortality outcomes, while processed fruit or vegetable consumption showed consistent inverse associations. Conclusions Our results suggest that traditional eating habits may contribute to the poor health status, particularly the high CVD mortality rates, of populations in Eastern Europe. Adequate public health nutritional interventions in this region are essential. Key messages This work indicates that traditional dietary habits in Eastern European countries may be one of the reasons for the poor health status of populations in this region. Public health nutritional interventions which target traditional but unhealthy foods, such as lard, have the potential to considerably improve population health in Eastern Europe.