The authors report their observations on 7 cases of multiple malignant tumors during the period 1988/1992 (frequency of 0.03 x 100). They report that primary malignant tumors involved the laryinx and the wang, and both the lungs in a synchronous or metacronous way. They suggest that pathogenesis of multiple malignant tumors may be very similar to that of multiple endocrinous neoplasms.