Complex and interrelated factors contribute to the observed disparities in cancer incidence and death among racial, ethnic, and under-served groups. The most obvious factors are associated with a lack of health care coverage and low socioeconomic status (SES). SES is most often based on a person’s income, education level, occupation, and other factors, such as social status in the community and where he or she lives. Studies have found that SES, more than race or ethnicity, predicts the likelihood of an individual’s or a group’s access to education, certain occupations, health insurance, and living conditions—including conditions where exposure to environmental toxins is most common—all of which are associated with the risk of developing and surviving cancer. SES, in particular, appears to play a major role in influencing the prevalence of behavioral risk factors for cancer (for example, tobacco smoking, physical inactivity, obesity, and excessive alcohol intake, and health status), as well as in following cancer screening recommendations. Research also shows that individuals from medically under-served populations are more likely to be diagnosed with late-stage diseases that might have been treated more effectively or cured if diagnosed earlier. Financial, physical, and cultural beliefs are also barriers that prevent individuals or groups from obtaining effective health care.