Approaches to calculation of a cumulative rating of an advertizing campaign with the account of advertizing forgetting are considered. Factors of advertizing forgetting are offered. Calculations of a cumulative rating of an advertizing campaign with the account of advertizing forgetting by various techniques are carried out. The optimizing problem of media planning of minimization of the budget on advertizing placing at restrictions on one-stage reach and an indicator of a cumulative rating of an advertizing campaign with the account of advertizing forgetting is formulated.