Manifestations of simple and complicated forms of memory have been studied in persons of both sexes at different age. It has been established that volume of the short-term memory for numbers (simple memory) as well as the speed of solving logical problems (complicated mnemic activity) depend on both age and sex of subjects. 5-10 years old girls are found to be better at memorizing numbers and they solve logical problems better than boys of the same age. With age the picture becomes reversed. Weakening of memory is observed in women at an earlier age than in men. In both sexes mnemic activity is at its highest peak at the time of graduation from school - at 15-17 years.