Exacerbating factors of tuberculosis were evaluated from the viewpoint of intractability of the disease including the effectiveness of chemotherapy by comparing patients with intractable tuberculosis and those with nonintractable tuberculosis. Of the patients aged 30 years or above admitted to our hospital for the initial episode of tuberculosis, 42 patients with intractable tuberculosis and 247 controls were compared. No difference was observed between the two groups in life-style factors such as smoking, drinking, and living alone or complications such as diabetes mellitus and cerebrospinal diseases. In the refractory group, a poor general condition with fever and body weight losses on admission, massive discharge of tubercle bacillus, and delayed diagnosis and treatment were frequently observed. Also, patients with a lymphocyte count of 500/mm3 or less such as those with anemia, hypoproteinemia/hypoalbuminemia, high LDH and CRP levels, and a low cholinesterase level were significantly more frequent, and resistant bacteria were detected more frequently in this group.