Double lung nodules are not necessarily lung cancer. In addition to malignant lung lesions, benign lung lesions, such as pneumonia and tuberculosis, can also present as double lung nodules. A double lung nodule is a lesion in the lung that is less than 3 cm in diameter, and those larger than 3 cm are called masses. The presence of double lung nodules is determined by a combination of factors such as the nodule’s nature, size, location, and family history. Most pulmonary nodules are benign lesions, i.e., inflammatory pseudotumors, commonly associated with pulmonary tuberculosis. Only a small percentage of pulmonary nodules are manifestations of lung cancer. Single pulmonary nodules are seen in the early stages of malignant lesions, and occasionally multiple cases are seen. When the nodules in both lungs are small, patients often do not feel any discomfort and do not need any special treatment and regular review is sufficient. However, if the nodules in both lungs suddenly increase in size, and the patient develops cough, dyspnea, or even blood in the sputum, the patient should promptly visit the respiratory medicine department for further examination to clarify the cause and timely treatment. Double lung nodules need to be taken seriously because lung nodules and lung cancer are closely related. Once double lung nodules are found, regular follow-up examinations should be conducted to understand the changes of nodules.