The primary purpose of this study was to examine the role of conscious self-regulation in reliability of actions of students in exam situation. Participants were 231 16—18 year old students. The results showed that reliability of regulation (stability of the basic regulatory characteristics in a stressful situation) is the basis of the reliability of action of students with different level of academic success. The study describes the characteristics of the reliability of learning actions of students. We compared personal and regulatory characteristics of high school students with different level of reliability of actions and academic success. We found that students with the highest score on the exam have a low level of anxiety and a high level of conscious self-regulation (especially regulatory reliability). The results of research suggest that individual system of self-regulation plays a significant role in reliability of actions of students in exam situation and provides new information about how we can ensure reliability of actions of students in exam situation.