Five Colombian cities: Villavicencio, Pereira, Cucuta, Bucaramanga and Bosa.To describe the knowledge, attitudes and practices related to tuberculosis (TB) in household contacts (HHCs) of TB patients.A cross-sectional study was conducted. The estimated sample size required was 855. The World Health Organization guide 'Advocacy, communication and social mobilization for TB control: a guide to developing knowledge, attitude and practice surveys' was translated into Spanish and adapted to the dialect of each city. HHCs were invited to participate in the study and included if they agreed.We interviewed 878 HHCs. Most of them knew that TB was transmitted by airborne droplets; however, 52.2% also said that TB could be transferred from one person to another by sharing plates or clothes or shaking hands. Fifty-five per cent of HHCs acquired TB-related information from health care workers, and 44% from family members and friends. Fear was the main reaction reported by HHCs when they were informed of a TB diagnosis (60%). Eighty-five per cent of HHCs answered that the community rejects or avoids TB cases.There are significant gaps in the knowledge about TB and the stigmatisation associated with it. Educational strategies should be designed together with the community to demystify many misconceptions about TB.