[en] This paper presents the medical monitoring results of 300 children (3-14 years old) of the first generation of Chernobyl liquidators living in the same region of the Russian Federation (Obninsk-city). The monitoring was performed in a period of 1994-2002. Results showed an annual increase of a number of new cases of hereditary anomalies (Q00-Q99) in particular in 1997 and 1999 years, diseases of blood and hemopoietic organs (D50-D89) in a period of 1994-1999, endocrine system and metabolic diseases (E00-E90) including thyroid hyperplasia from the year 1997, mental and behavior disorders (F00-F99, G00-G99) beginning from the year 1999. More frequent cases of hereditary anomalies in children of liquidators were anomalies of digestive organs (Q38-Q45) and urine pathways (Q60-Q64), but in the control group it was anomalies of the musculoscelenal (Q65-Q79) and circulatory system