In Taiwan, which is an endemic area for tuberculosis, coexisting pulmonary tuberculosis and lung cancer may pose both a diagnostic and a treatment challenge to the clinician. We present the case of a 60-year-old female with multiple pulmonary nodules. The initial diagnosis of pulmonary tuberculosis was made by the pathological finding of a left lower lung nodule. The initial treatment response was fair, before a 3-month gap in follow-up. However, miliary carcinomatosis developed later and tissue proof of a right lower lung nodule revealed adenocarcinoma. When encountering a patient with multiple pulmonary nodules in an endemic area for tuberculosis, the possibility of a coexisting etiology other than tuberculosis should always be kept in mind; close monitoring of the treatment response is mandatory.