Background. The authors have attempted to assess the frequency of occurrence of congenital organ defects and hypothyroidism in Down’s Syndrome (DS) children rehabilitated on an outpatient basis. Trisomy of the 21st chromosome pair can be a cause of many diverse somatic defects, which can be detected in comprehensive clinical diagnosis.Material and methods. A retrospective study was performed on the basis of existing medical documentation for 527 DS children ranging in age from 0-18, registered in the period 1993-2000. Results. Cetogenetic testing performed on 497 patients with the characteristic phenotype picture revealed simple trisomy of the 21st chromosome pair in 475 cases (95% of the total population), Robertson translocation in 20 cases (4.2%), and a mosaic arrangement in 4 cases (0.8%). The occurrence of congenital heart defects in DS children was noted in 254 cases (48.2% of the total), vision defects in 238 (45%), hearing defects in 54 (10%), bone and joint defects – in the form of developmental anomalies of the spine, rib cage, upper limbs, and lower limbs – in 113 (21.4%). Other defects occurred less often: urogenital defects in 40 cases (7.6%), digestive tract defects in 29 cases (5.5%) and respiratory defects in 23 cases (4.4%). Congenital hypothyroidism confirmed by testing the level of TSH was found in 112 children (21.3%). Conclusions. The diversity of disturbances seen in DS children requires early, comprehensive diagnosis and developmental rehabilitation, a conductive family environment, and broad social support.