Disclosed are system and method for distributing most effective antivirus records to user devices. An exemplary method includes: collecting, by a server, statistics on the use of a plurality of antivirus records deployed on a plurality of user devices; calculating, by the server, a coefficient of effectiveness of each antivirus record based on the collected statistics on the use of the plurality of antivirus records by the plurality of user devices; identifying, by the server, a group of the plurality of antivirus records having the largest coefficients of effectiveness, wherein the group is a number of the plurality of antivirus records not exceeding a threshold value; and transmitting, by the server, the group of antivirus records to at least one of the plurality of user devices for storage in an antivirus database for use by an antivirus application of the at least one user device.