Аннотация: The article presents a study related to the study of the characteristics of the formation of logical thinking activity in primary school students. A total of 214 children participated in the study: 51 second-graders, 111 third-graders (62 - control group, 49 - experimental), 52 fourth-graders. With the students of the experimental group, 32 extracurricular classes (one per week) were held throughout the school year according to the author's program "Logic". As a result of diagnostics on the material of plot-logical problems developed by the author, it was shown that in children who studied according to the school program and solved problems according to the "Logic" program, logical thinking activity was formed at a higher level than in children who studied only according to the school program.