Vitamin D was used to treat tuberculosis in the pre-antibiotic era. New insights into the immunomodulatory properties of 1alpha,25-dihydroxy-vitamin D have rekindled interest in vitamin D as an adjunct to antituberculous therapy. We describe the historical use of vitamin D in tuberculosis treatment; discuss the mechanisms by which it may modulate host response to infection with Mycobacterium tuberculosis; and review three clinical trials and ten case series in which vitamin D has been used in the treatment of pulmonary tuberculosis.