Alcohol consumption is causally related to cancer of the upper aero-digestive tract, liver, colon, rectum, female breast and pancreas. The dose response relationship varies for each site. We calculated Ireland's cancer incidence and mortality attributable to alcohol over a 10-year period. Between 2001 and 2010, 4,585 (4.7%) male and 4,593 (4.2%) female invasive cancer diagnoses were attributable to alcohol. The greatest risk was for the upper aero-digestive tract where 2,961 (52.9%) of these cancers in males and 866 (35.2%) in females were attributable to alcohol. Between 2001 and 2010, 2,823 (6.7%) of male cancer deaths and 1,700 (4.6%) of female cancer deaths were attributable to alcohol. Every year approximately 900 new cancers and 500 cancer deaths are attributable to alcohol. Alcohol is a major cause of cancer after smoking, obesity and physical inactivity. Public awareness of risk must improve. Over half of alcohol related cancers are preventable by adhering to Department of Health alcohol consumption guidelines.