The aim of the study was to explore the relation between hospitalization and the success of therapy in lung tuberculosis. Three hundred and fifty one hospitalized human immunodeficiency virus (HIV) negative, smear positive cases of pulmonary tuberculosis were studied. All cases were World Health Organization (WHO) category 1 patients. The patients with chronic additional disease and those who developed complication during therapy were excluded. Three hundred and six outpatients attending to local dispensaries were also included as control group. The groups were compared with respect to completion rates at 6 months of therapy. The average age was 37.48 + or - 13.87 years; 204 patients were women (31.1%). For inpatients, mean hospital stay was 25.4 + or - 14.2 days. A total of 304 (86.6%) hospitalized patients completed their treatment; the remaining 47 (13.4%) cases were not followed-up. No significant relation was observed between the length of hospital stay and completion of therapy (p> 0.05); 295 (96.4%) outpatients successfully completed their treatment. The probability of not completing the therapy was significantly higher for hospitalized patients (RR: 3.72 95% CI: 1.96-7.05 p< 0.05). Our results show that in category 1 patients without concomitant disorders, initiation of treatment at hospital has an adverse influence on the outcome of treatment, as reflected by the percentage of completers.