Objective: to analyze the impact of the degree of a family cancer history on the rate and nature of primary multiple malignant neoplasms (PMMNs). Subjects and methods. Additional medical information on the probands of 3952 families from the Moscow Family Cancer Register was obtained at least 5 years after their initial registration. The sample was divided into 4 groups according to the degree of their family history of cancer (none, mild, severe) or those of its syndromes; standard biometric assays were applied. Results. In the syndrome group, the rate of PMMNs was significantly higher than that in the other groups; the rate of PMMNs with 3 or more malignant neoplasms (MNs) and that of new MNs were significantly higher than that in the syndrome and family cancer history groups as compared to the similar indicators in the groups with a family of none and mild cancer. No significant differences were found between the family cancer history groups in the relative rate of synchronous (27.60%), metachronous (69.53%), and mixed (2.87%) PMMNs, in the rate and concurrence of individual localizations of MNs and in the sequence of their emergence in metachronous PMMNs. Conclusion. The degree of a family cancer history affects the rate of PMMNs, that of PMMNs with 3 or more MNs, and the incidence of new MNs; it has no impact on the types of PMMNs, the involvement of individual locations, and the sequence in MNs in PMMNs.