A case of spontaneous regression of multiple pulmonary metastases of transitional cell carcinoma is reported. Spontaneous regression of metastatic pulmonary lesions seldom occurs in transitional cell cancer, and only 3 such cases have been reported in the literature. A 42-year-old male with multiple pulmonary metastases which had regressed spontaneously for a significant period of time is herein reported. The lesions were shown to be transitional cell carcinoma, originating from the left renal pelvis. The serial immunological examinations suggest that the phenomenon might be attributed to the augmented immune response of the patient.