To prospectively evaluate the associations of dietary calcium and magnesium intake with cancer incidence and mortality, data of 24,323 participants of the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg), who were aged 35-64 years and cancer-free at recruitment (1994-1998), were analyzed using multivariate Cox regression models. After an average follow-up time of 11 years, 2,050 incident cancers were diagnosed and 513 cancer deaths occurred. Dietary calcium intake was inversely but not statistically significantly associated with colorectal cancer risk (hazard ratio [HR] for per 100 mg increase in intake: 0.95; 95% confidence interval [CI]: 0.88, 1.02) and lung cancer risk (HR for per 100 mg increase in intake: 0.94; 95% CI: 0.87, 1.02). No statistically significant associations were observed between dietary calcium intake and site-specific or overall cancer incidence or mortality. Dietary magnesium intake was not statistically significantly associated with any of the investigated outcomes. This prospective cohort study provides no strong evidence to support that high dietary calcium and magnesium intake in the intake range observed in a German population may reduce cancer incidence or mortality.