Accumulating evidence suggests that vitamin D may protect against cancer, but results from epidemiologic studies are inconclusive so far, and other studies looking into the prospective association of total cancer mortality and serum 25-hydroxyvitamin D [25(OH)D] levels, which are considered to be the best indicator of vitamin D status, are scarce. We measured 25(OH)D and 1,25-dihydroxyvitamin D in 3,299 patients from the Ludwigshafen Risk and Cardiovascular Health study. The baseline examination was done between July 1997 and January 2000 and included a fasting blood sampling in the morning before coronary angiography. During a median follow-up period of 7.75 years, 95 patients died due to cancer. After adjustment for possible confounders, the Cox proportional hazard ratio (95% confidence interval) of the fourth 25(OH)D quartile was 0.45 (0.22-0.93) when compared with the first quartile and the hazard ratio per increase of 25 nmol/L in serum 25(OH)D concentrations was 0.66 (0.49-0.89). We found no association between serum 1,25-dihydroxyvitamin D levels and fatal cancer. In summary, our data suggest that low levels of 25(OH)D are associated with increased risk of fatal cancer in patients referred to coronary angiography and that the maintenance of a sufficient vitamin D status might therefore be a promising approach for the prevention and/or treatment of cancer.