Objective: the study is concerned with the analysis of influence of severity and presence of certain phenotypic signs of nonspecific dysplasia of connective tissue (NDCT) on manifestation and rate of progression of funnel chest deformity (FCD) in children. Materials and methods. 98 patients with FCD aged from 4 to 18 years have been examined. The degree of FCD has been estimated by the index of Gizhytskaya (IG). The structure of phenotypic signs of NDCT has been determined according to M. J. Glesby (1989), the severity of the NDCT has been evaluated by L. N. Phomina tables (2000). Results. It is established, that the degree of FCD in children is significantly associated with severity of NDCT. Conclusion. Prognostically unfavourable factor for rapid progression of FCD in children has been determined by the prevalence of skeletal and articular manifestations among phenotypic signs of NDCT against the background of minimal changes of the skin.