This study aimed to compare mortality from cancers between ethnic German immigrants and the native German population. We conducted a retrospective cohort study of 34,393 so-called Aussiedler from the Former Soviet Union in Germany's largest federal state and ascertained vital status and cause-of-death through population registries. We used direct and indirect standardisation to compare Aussiedler, German and Russian federation rates, and Poisson regression for influencing factors. Compared to Germans, male Aussiedler had similar all-cancer mortality, standardised mortality ratio (SMR) 0.97 (95% confidence interval: 0.86-1.10), higher mortality from lung and stomach cancers, and lower mortality from prostate cancer; SMR 0.48 (0.25-0.84). Females had lower all-cancer, lung, and breast cancer mortality with SMR (95% CI), 0.76 (0.67-0.89), 0.61 (0.34-1.01) and 0.47 (0.29-0.70), respectively. Compared to the Russian Federation, Aussiedler had lower all-cancer mortality; males had similar mortality from lung cancers. Better health care in Germany could have resulted in reduced mortality from certain cancers among Aussiedler.