Colorectal cancer (CRC) screening with faecal occult blood test (FOBT) has the potential to reduce the incidence and mortality of CRC. Screening uptake is known to be inferior in people with low socioeconomic position (SEP) when compared with those with high position; however, the results of most previous studies have limited value because they are based on recall or area-based measures of socioeconomic position, and might thus be subject to selective participation and misclassification. In this study we investigated differences in CRC screening participation using register-based individual information on education, employment, and income to encompass different but related aspects of socioeconomic stratification. Also, the impact of ethnicity and cohabiting status was analysed.