Background: Cancer is one of the leading causes of death in Korea. To reduce cancer incidence, the Korean National Cancer Center (KNCC) has been expanding its organized cancer screening program. In addition, there are opportunistic screening programs that can be chosen by individuals or their healthcare providers. The purpose of this study was to investigate factors associated with participation in organized and opportunistic cancer screening programs, with a particular focus on socioeconomic factors. Materials and Methods: We used data from the Korea National Health and Nutrition Examination Survey (KNHANES), a cross-sectional nationwide study conducted by the Korean Ministry of Health and Welfare from 2007 to 2011. The study included information from 9,708 men and 12,739 women aged 19 years or over. Multinomial logistic regression analysis was conducted, adjusting for age, year of data collection, residential region, current smoking status, current alcohol consumption status, exercise, marriage status, job status, perceived health status, stress level, BMI, limitation of activities, cancer history, health insurance type, and private insurance status, to investigate the association between education level, economic status, and cancer screening participation. Results: In terms of education level, disparities in attendance were observed only for the opportunistic screening program. In contrast, there was no association between education level and participation in organized screening. In terms of economic status, disparities in opportunistic screening participation were observed at all income levels, but disparities in organized screening participation were observed only at the highest income level. Conclusions: Our findings reveal that socioeconomic factors, including educational level and economic status, were not significantly associated with participation in organized cancer screening, except at the highest level of income.