Infants born prior to the term of 36 gestation weeks and 6 days are considered preterm infants. The number of preterm infants in Lithuania amounts to 5 – 6% per year. The most significant health problems of such infants in the neonate period are caused by immaturity of the organs and their systems. Knowledge of a preterm infant’s psychomotoric development contributes to early notification of disorders, more effective composition of problem-orientated corrective programs and monitoring of development progress. According to the reference literature, early application of physical therapy enables recovery of as much as 50 percent of infants and improvement of the condition of the rest. The goal of this thesis is to determine within which group: in the preterm infants (extremely preterm (born within 25-30 gestation week) or very preterm infants (born within 31-36 gestation week)), physical therapy has major effect for the emergence time of motor function. The objectives of the thesis are as follows: 1. Comparison of emergence time of motor functions with regard to extremely preterm and very preterm infants within the same stage of corrected age. 2. Comparison of motor development of the extremely preterm and very preterm infant groups and within each separate group considering the gender aspect. 3. Comparison of motor development alternation of the extremely preterm and very preterm infant groups and within each separate group considering the aspect of applied surgical treatment... [to full text]