Resettlers (in German: (Spät-)Aussiedler) form one of the biggest migrant groups in Germany. It is known that migrants have different mortality patterns compared to the autochthon population. In this paper, we combined data from three resettler cohorts and examined differences in mortality from non-communicable diseases among resettlers in Germany and the German population. Furthermore, we investigated time trends of cause-specific mortality for 20 years of follow-up and compared it with the German mortality rates. To assess differences in cause-specific mortality between resettlers and the general German population, we calculated standardized mortality ratios (SMRs). To ascertain mortality trends, cause-specific age-standardized mortality rates were calculated and modeled with Poisson regression and fractional polynomials. During the observation period, the study population accumulated almost 800,000 person-years and 5572 deaths were observed. All-cause mortality among resettlers was lower (SMR = 0.91, 95% CI = 0.89–0.94) compared to the general German population, as well as cardiovascular diseases (CVD) mortality (SMR = 0.82, 95% CI = 0.79–0.86). Results for cancer mortality varied considerably by cancer site. Analyses of time trends showed that all-cause and CVD mortality were decreasing over time in resettlers, as well as in the general German population. Lower all-cause mortality among resettlers is mainly explained by lower CVD mortality. Cancer-site specific mortality showed different results. Converging mortality rates may indicate an adaption of lifestyle behavior. However, there are no data on individual risk factors in this study.