The authors report a case of thrombocytopenia associated with miliary tuberculosis. The patient was a 28-year-old woman who was admitted because of massive upper gastrointestinal hemorrhage and acute respiratory failure. Chest radiographs revealed diffuse bilateral reticulonodular infiltration and complete blood count was significant for severe thrombocytopenia. Bone marrow biopsy was performed to investigate the cause of thrombocytopenia and demonstrated multiple tiny caseating granulomas suggesting miliary tuberculosis (TB). She received anti-TB therapy and a short course of steroid with good response. Platelet count returned to normal limit within 10 days. Although isolated thrombocytopenia is uncommon in TB, it is still important to consider TB in the differential diagnosis of thrombocytopenia, particularly in patients with abnormal chest radiographs. Bone marrow examination is very helpful in this situation.