The purpose of this study is to determine whether an alternative drug, (rifampin) given daily, is better at treating tuberculosis (TB) and more tolerable than the usual drug treatment, isoniazid (INH). Study participants will include 972, TB infected, San Francisco Jail inmates, aged 18 or older. One group of volunteers will take INH two times a week for 9 months, and the other group will take rifampin daily for 4 months. Medication will be administered in jail and at the San Francisco TB Clinic if the volunteer is released from jail prior to completing the study. Participants will be seen daily for 4 months (rifampin group), and 2 times a week for 9 months (INH group) for directly observed therapy. Study procedures will include 5 symptom review visits and blood samples for lab testing. Follow-up will continue for each subject for five years after enrollment into the study.