Objective: Analysis of the incidence of selected types of birth defects in the Czech Republic in the period of 1961 – 2005. The mapping of the mean incidences of selected diagnoses of birth defects in the course of 45 years in the Czech Republic. Type of study: Retrospective epidemiological analysis of incidences of birth defects from the database of National Registry of birth defects in the Czech Republic. Materials and methods: The paper employed data from the registry of birth defects held in the Institute for the Care of Mother and Child (1961 – 1993) and the all-republic registry of birth defects held in the Institute of Medical Information and Statistics of the Czech Republic in the period of 1994 – 2005. Incidences of birth defects were analyzed in prenatally and postnatally diagnosed cases and the mean frequencies were established for the whole period of time observed. Results: In the period of 1994 – 2005, 6 067 798 children were born in the Czech Republic. There were diagnosed on the whole 2,028 cases of anencephaly, 2,647 cases of spina bifida, 462 cases of encephalocoele, 5,137 cases of the defect of neural tube in total, 3,904 cases of birth hydrocephalus, 1,627 cases of omphalocoele, 941 cases of gastroschisis, 2,564 cases of the defect of abdominal wall, 1,426 cases of diaphragm hernia, 1,683 cases of cystic kidneys, 1,389 cases of agenesis/hypoplasia of the kidney, 6,018 cases of the Down syndrome, 960 cases of birth defects of esophagus, 1,629 cases if anorectal malformations, 6,749 cases of cleft lip and/or palate and 4,356 cases of cleft palate. The mean incidences were as follows: 3.30 for anencephaly, 4.35 for spina bifida, 0.79 for encephalocoele, 8.43 in the defect of neural tube, 6.23 in birth hydrocephalus, 2.68 in encephalocoele, 1.761 in gastroschisis, 4.28 in the defects of abdominal wall, 2.33 in diaphragm hernia, 2.98 in cystic kidneys, 2.51 in agenesis/hypoplasia of the kidney, 10.71 in the Down syndrome, 1.70 in birth defects of esophaghus, 2.72 in anorectal malformations, 11.00 in cleft lip and/or palate and 7.23 in cases of cleft palate per 10,000 individuals born alive. Conclusion: The paper presents most recent results of the analyses of incidences of birth defects in the Czech Republic in the course of the 1961 – 2005 period of time. Some of the followed birth defects were decreasing (defects of neural tube), some were on the increase (defects of abdominal wall, birth defects of esophagus and anorectal malformations). The other frequencies were changing due to better and earlier diagnostics (birth defects of the kidneys), frequencies in the other defects remained unchanged (diaphragm hernia) or fluctuated (cleft face, Down syndrome).

        Key words: in born defect, anencephaly, spina bifida, encephalocoele, defects of neural tube, birth hydrocephalus, omphalocoele, gastroschisis, abdominal wall defects, diaphragm hernia,