OBJECTIVE: To estimate the prevalence of pulmonary tuberculosis and to analyze the utilization of health services, in coughers seeking care at primary care centers, within areas of "severe" and "very severe" poverty, in the Border Region of Chiapas, Mexico. MATERIALS AND METHODS: In 1997 an active case finding of patients with cough was carried out among all patients aged over 14 years seeking consultation (n = 2.203) in a random sample of seven primary care centers; 573 coughers were found. RESULTS: A rate of 11.1 positive pulmonary tuberculosis per hundred patients was found (95% CI = 6.6-17.2). The factors associated with positive pulmonary tuberculosis were size and poverty level of the locality of residence. Fifty-six percent of the coughers sought care for non-respiratory symptoms. CONCLUSIONS: It is necessary to improve detection and control of pulmonary tuberculosis at the primary care centers, as well as to develop a health education campaign among the general population, with the aim of increasing the demands for care among coughers and reduce the time elapsed between onset of cough and first medical care.