Spontaneous regression of malignant tumours is a rare and enigmatic phenomenon. We reviewed the cases of spontaneous regression of cancer in medical literature according to MEDLINE database in the period 1988-2006 and compared them with similar reviews from 1900-1987 period. The number of reported cases of spontaneous regression increased steadily in XX century, probably due to a rising interest in this problem and new possibilities of radiological and biopsy examinations. Spontaneous regression of malignancy was reported in almost all types of human cancer, although the greatest number of cases in years 1988-2006 were reported in patients with nephroblastoma, renal cell carcinoma, malignant melanoma, lymphoma. Elucidation of the process of spontaneous regression offers the possibility of improved methods of preventing andlor treating cancer.