Background: African Americans have higher incidence of cancer and lower survival rates compared to other ethnicities. We studied the 5-year relative survival between black and white races for the most common cancers in the United States. Methods: Data was obtained from the SEER database, the largest population-based cancer database including 28% of US population. Data containing 5-year relative survival from the patients who were diagnosed from 1973 to 2010. We included data for cancers of colorectal, lung, prostate, breast and melanoma, the most common cancers in the United States. Results: For colorectal cancer average 5-year relative survival from 1973 to 2010 is 59.9% for whites and 51.5% for blacks. Same results for lung cancer are 14.6% for whites and 12.2% for blacks, for breast cancer is 84.5% for whites and 71.6% for blacks, for prostate cancer is 86.9% for whites and 80.5% for blacks, and for melanoma is 87.9% for whites and 66.4% for blacks. The average black to white 5-year relative survival ratio is 0.86, 0.84, 0.85, 0.92, and 0.76 for cancers of colorectal, lung, breast, prostate, and melanoma, respectively. This ratio has decreased from 0.89 to 0.86 and from 0.87 to 0.81 for colorectal and lung cancer, respectively and for cancers of breast, prostate and melanoma it has increased from 0.85 to 0.87, from 0.88 to 0.89, and from 0.73 to 0.80 respectively. Conclusions: Our analysis shows that for colorectal and lung cancer the survival rate difference between blacks and whites has increased over 4 decades but for cancers of breast, prostate and melanoma this ratio has decreased. Better understating of the factors contributing to racial differences in cancer survival has potential applicability in policymaking for a better and equal health care delivery.