Immunodeficiency diseases (IDD) are the basis of increased incidence and morbidity of acute and chronic pathology. Structural and/or functional defects of the immune system, associated with gene mutations, complicate the diagnosis of disease and the choice of treatment options, by virtue of their clinical polymorphism, the complexity of diagnosis and the increasing incidence. Adverse ecological situation in Moldova, established by virtue of intensive and prolonged use of pesticides, updated medical and social problems and the growth of the total incidence may be important regional factors in the genesis of IDD. The absence of the National Register of IDD does not allow the monitoring of this nosological forms of pathology. The purpose of this research is to study the epidemiological, clinical, immunological and molecular genetic features of the IDD in areas with high anthropogenic load. Screening and modern methods of research (clinical, instrumental, functional, lymphocyte phenotyping using IFR with monoclonal antibodies anti-CD, determination of the concentration of immunoglobulins of М, G, А, Е classes in the blood serum, genetic analysis of Btk, CD40L, TACI, WAS, ATM, NBS, SH2DI, ELANE genes, using SSCP, PCR methods) were used. Complex clinical, immunological and partly genetic testing of 118 patients with suspected IDD aged from 3 days to 19 years was carried out. The specific feature of clinical manifestations of pathologies in these children was the prevalence of the association of several nosological forms (65.3%), and more often: pathology of bronchopulmonary tract (72.9%), allergic diseases (27.1%), abnormal development (20.2%) and gastrointestinal pathology (22%). Testing of immune status has demonstrated the imbalance of indices of both humoral and cellular immunity. In the total number of patients 3 cases of IDD were found. Thus, a complete clinical, immunological and molecular genetic study of patients allowed to establish the first cases of primary immunodeficiencies within screening of sick children in Moldova.