This study assesses risk factors for treatment noncompliance by patients registered with the Tuberculosis Control Program who live in the urban area of Pelotas, Rio Grande do Sul State. The study lasted from June 1994 to December 1995. All new cases diagnosed as pulmonary tuberculosis in the 20-80-year age bracket were monitored by the Tuberculosis Unit, hub of the tuberculosis control program in Pelotas. All patients was monitored from time of diagnosis through end of treatment, six months later. Patients answered a standard questionnaire. From June 1994 to June 1995, 152 cases were recorded, with some 20% treatment noncompliance. We observed no significant association between noncompliance and employment status for head-of-family, age, gender, alcoholism, or presence of symptoms, while the only risk factor significantly associated with noncompliance was non-white skin color, probably due to the study's weak power as a function of sample size.