OBJECTIVES: The aim of the study was to test the hypothesis that worsening mortality rates in the early 1930s were associated with increasing votes for the Nazi Party. STUDY DESIGN: The study consist of panel data with fixed effects. METHODS: We used district- and city-level regression models of Nazi vote shares on changes in all-cause mortality rates in 866 districts and 214 cities during federal elections from 1930 to 1933, adjusting for election and district/city-level fixed effects and sociodemographic factors. As a falsification test, we used a subset of deaths less susceptible to sociopolitical factors. RESULTS: Historical downward trends in mortality rates reversed in the early 1930s in Germany. At the district/city level, these increases were positively associated with a rising Nazi vote share. Each increase of 10 deaths per 1000 population was associated with a 6.51-percentage-point increase in Nazi vote share (95% confidence interval = 1.17-11.8). The strongest associations were with deaths due to infectious and communicable diseases, suicides, and alcohol-related deaths. Worsening mortality had no association with votes for the Communist Party or for other contemporary political parties. Greater welfare payments were associated with smaller increases in both mortality and Nazi vote share, and adjusting for welfare generosity mitigated the association by approximately one-third. CONCLUSIONS: Worsening mortality rates were positively associated with the rise of the Nazi Party in 1930s Germany. Social security mitigated the association between mortality and Nazi vote share. Our findings add to the growing evidence that population health declines can be a 'canary in the coal mine' for the health of democracies.