This research was developed in 1995-1996 in the Oliveira Pombo Health Center (CSOP), Fortaleza, Ceará, Brazil. The aim was to explore factors influencing non-adherence to tuberculosis treatment. Specific objectives were: dynamics of tuberculosis notification and treatment of non-adherence cases at the CSOP; demographic, social, economic, and cultural profiles of clientele (social actors); default reasons that interrupt treatment; and knowledge and perception of the disease. The methodological approach was based on descriptive epidemiology and on sociological interpretivism. A semi-structured interview was used for questions related to the social actors, such as: demographic, social, economic, cultural, and behavioral factors; knowledge and perceptions of tuberculosis and treatment; impact of the disease on patients' lives; and perspectives concerning health service attendance. Results show that treatment non-compliance involved multiple and complex interrelated factors.