OBJECTIVES: It is intended to describe the characteristics of the birth defects in 52,744 births in 4 Colombian cities. A congenital malformation (CM) is defined as an alteration of the morphology that can be diagnosed at the pre or postnatal period. The Colaborative Latin-American congenital malformations study (ECLAMC) was established since 2001 at the Human Genetics Institute at the Pontificia Universidad Javeriana. The objective of the latter study is to do a surveillance of all newborns in order to diagnose them promptly and to establish possible risk factors involved in the development of CM. METHODS: We used the data base registered from 4 different cities in Colombia during the period between April 2001 to January 2008. The cases were all newborns with any weight at the moment of birth or any stillbirth above 500 gr. The controls were all healthy newborns from the same sex as the cases. It was excluded a case or a control if the mother did not accepted to participate in the study. RESULTS: The population of the study was 52.744 newborns from which 1650 (3,12%) had a MC. The majority of cases were male and the most common CM was the group of the ear anomalies followed by clubfoot, polydactyly, Down syndrome, nevus, cleft palate and cardiopathies. The weight and gestational age were less in the group of the cases compared to the controls (p <0,001). It was used the prognostic scale for each MC and it was found that the majority of cases had a high risk of permanent disability if not treated (54%).CONCLUSIONS: In this study are reported frequencies of the CM in a sample of newborns to 4 Colombian cities found prevalence similar to the rest of the world. These diseases contribute significantly to the burden of disease in our country and directly impacting infant mortality rates.