One hundred rural patient with pulmonary tuberculosis and 74 urban patients were included in the study in order to study the main causes of non-compliance. Crude cumulative incidencia was 42% (73/164). Those factors with the strongest association with non-compliance, independently of its association with other factors, were to live in rural areas (OR 0 10.4; p < 0.001), had not gone to school (analfabet) (OR = 4.5; p < 0.001), and last more than an hour to reach the medical care unit (protector) (OR = 0.40; p = 0.07). No association was found with socioeconomic factors, neither with the patient's knowledge of the disease. Identifying those factors related to non-compliance is important, since non-compliance occurs in the very firsts days of treatment, when the shortage of treatment or giving fewer pills do not work at all. To get a better medial control may be a good way to reach the expected control of the disease.