We report 3 patients with chronic myeloproliferative syndromes and active tuberculous infection. The first patient had chronic myelocytic leukemia. In this patient, primary tuberculosis was localized in the lung. In spite of tuberculostatic treatment, he developed laterocervical lymphadenopathy and a tuberculous abscess in right lower limb. The second patient had agnogenic myeloid metaplasia. In this patient splenic tuberculosis (TBC) with subsequent pulmonary involvement were diagnosed. The third patient had idiopathic thrombocytopenia with pulmonary tuberculous infection. In two patients, tuberculosis was diagnosed some time after the diagnosis of hematologic disease, while in the third one both conditions were simultaneously identified. One of the patients died of complications of alkylating therapy, and the other two are still alive. In none of the three patients there has been evidence of active tuberculous infection after therapy, although their course has been slow and two have required associated surgery to eradicate the infection. We review the hematologic conditions which can develop during tuberculosis, the incidence of this infection during chronic myeloproliferative syndromes, the possible pathogenetic relation between both conditions, and the clinical presentation of tuberculosis in these patients, which usually is disseminated in character.