Introduction: One of the commonly used terms in the assessment of CNS functioning is muscle tone. In literature we can find many different and not standardized definitions. Postural tone depends on topographic distribution in proximal and distal parts of body and antigravital activity. For diagnostic and therapeutic purpose the term postural tone is used. The aim of this study was to assess (monitoring) the psychomotor development of infants between 2 months and 2 years of life with abnormal posture tone (hypotonia of posture) and asymmetry of postural and motor patterns. Infants participated in NDT-Bobath therapeutic intervention.Material and methods: 65 infants fulfilling specified criteria were examined during 2 years of prospective study. According to hypotonic type, infants were divided into two groups. The presence of asymmetrical tonic neck activity in spontaneous movements was coded in two-points scale (1 or 2).Results: All infants were examined at first visit with INSITE developmental scale which displayed psychomotor retardation. At the age of 2 years, only 21,87% from first group and 100% from second group still were assessed as retarded. Conclusions: Disintegrated activity ATOS decreased the level of motor development of 24-month-old infants even to 4 months of developmental age. In the second group, the number of infants with more disorders in quality of movement and decreased final developmental age is much bigger.