Pazopanib is an anti-angiogenic multi-targeted tyrosine kinase inhibitor used for treating soft tissue sarcomas and renal cell carcinoma. Although the occurrence of pneumothorax during pazopanib treatment has been recognized as an adverse event, there have been no reports of pneumothorax in patients treated with pazopanib. Here, we present the case of a 71- year-old male patient who developed pneumothorax during adjuvant pazopanib therapy after surgery for metastasized renal cell carcinoma. Left hilar and mediastinal lymph node swelling was detected in the postoperative surveillance after surgery, and radiological findings showed lymph node metastasis from renal cell carcinoma. Consequently, left upper lobectomy and mediastinal lymph node dissection were performed, and subsequent pathological examination confirmed the aforementioned diagnosis. Pazopanib was administered as an adjuvant therapy. However, the patient developed left pneumothorax on day 101. Although chest tube drainage was performed, massive air leak continued. A surgery was performed to repair the persistent air leak. This case demonstrates that pneumothorax should be recognized as an adverse event of pazopanib.