The article presents results of the research of relations between executive functions and prospective memory in primary school-age children with symptoms of subthreshold attention deficit hyperactivity syndrome (ADHD). The ADHD Assessment Scale ― ICD-10 criteria (Sukhotina, 2008) and Observation Form for Recording ADHD Behaviors During Academic Performance in the Clinic or in School) (Carter, 1994) were used to assess the symptoms of ADHD. Cognitive functions were assessed using the Wisconsin Sorting Card Test (Grant & Berg, 1948), Сanum (Gutierrez-Martinez, 2018), Вlock span (Isaacs, Vargha-Khadem, 1989), Digit span-backward (Wechsler, 1997), and measurement by Ana B. Cejudo (Cejudo, 2019). 51 children were recruited, 27 subjects were 6–7 years old and 24 subjects were 10 years old. All participants were divided into 2 control groups (children with typical development) and 2 experimental groups (children with symptoms of subthreshold ADHD). Overall, it was found that children in the group of 6–7 years old with symptoms of subthreshold ADHD have no significant differences with children from the control group in basal components of executive function: working memory, cognitive flexibility and executive attention. However, they show a decrease in learning abilities, self-regulation and an increase of non-perseverative errors along with the fall of event-based prospective memory. Children in the group of 10 years old with symptoms of subthreshold ADHD also showed the fall of learning abilities and prospective memory. The results of correlation analysis show that subjects with symptoms of subthreshold ADHD have changes in the systemic ― functional level which appear as a decreasing amount of links between executive functions and features of prospective memory.