The subject of this research is the psychological component of school adaptation among first-graders of public and sanatorium-based boarding schools. The author describes and compares the characteristics of psychological component of school adaptation. The goal consists in determination of peculiarities of the psychological component of school adaptation of elementary school students in the modern educational establishments of various types. The research involved 110 first-graders 7-8 years old (56 girls and 54 boys). The sampling is aligned by gender, age, and school. Research methodology contains the following projective techniques: ”Little Houses” by A. O. Orekhova; “Faces” by N. V. Lukyanchenko and T. L. Yadryshnikov; “House-Tree-Person” by J. Buck, with symptom complexes formulated by Bieliauskaitė. The method of descriptive statistics revealed that the majority of first-graders of sanatorium-based boarding school demonstrate negative emotions, insecurity, anxiety, lack of confidence in themselves,  inferiority feeling and depressiveness; while the majority of children of public schools experience emotional maladaptation, emotional tension towards mastering school subjects. Using Mann–Whitney U test, the author determines that the students o sanatorium-based boarding school much rarely demonstrate emotional towards school activity; emotional maladaptation is more characteristic to the students of public schools. The research materials are applied in educational process by the pedagogues, psychologists, and school administrations for determining the individual and differentiated approach towards students; as well as in a cycle of scientific and practical seminars for school pedagogues and parents of the students.