• Primary miliary tuberculosis of the liver was found in 12 cases under conditions showing that it is not rare but is easily overlooked as a possible cause of obscure illness. The symptoms found in all these case histories included fever, lassitude, weakness, anorexia, weight loss, chills, and drenching sweats. Reaction to the Muntoux test was positive in all. No cases of jaundice were seen. Hepatomegaly, splenomegaly, ascites, alcoholism, and exposure to tuberculosis are clues to the diagnosis. Needle biopsy of the liver is valuable but need not be done immediately in very weak patients, since recognizable tubercles remain in the liver for weeks after successful therapy has started. Isoniazid and aminosalicylic acid are now given to every patient, with streptomycin and steroids if necessary. The response in the cases here described was remarkably good, and sometimes dramatic. All of the eight patients whose treatment was considered adequate recovered without sequelae.