Thirty-six specific illnesses and injuries and 17 job hazards are assessed according to their contribution to absenteeism. Data are drawn from the 1977 Quality of Employment Survey, which is national probability sample of 1515 workers who worked 20 or more hours per week in 1977. Both frequencies and lengths of absences are analyzed. Illnesses and injuries that appear to contribute most to absenteeism are back injuries, broken bones, colds and flus, physical strain injuries, hits and falls, and joint inflammation. Job conditions resulting in the greatest amount of absenteeism are dangerous methods and machines, exertion, bad weather, human error, and dangerous workspaces. Although women reported physical strain injuries and working in awkward positions as the most frequent causes of absenteeism, men found back pain and working with dangerous machines to be the greatest causes of their absenteeism.