The paper brings forward the results of the study of mental states of first year students of the medical college. Degrees of expressiveness of such mental states as mental arousal, interest, emotional tonus, tension, and comfort have been identified. The author showed interrelation among mental states under study, and correlation of their degrees of expressiveness. The study revealed correlation of high level interest, high emotional tonus and medium level tension, which leads to a conclusion that medium level tension is a desired mental state for first year students. Insight into peculiarities of first year students’ mental states enables to predict and regulate their changes, as well as control efficiency and quality of learning activity.