Between 1988 and 1994 a national collaborative survey was carried out with the help of 129 previously trained pediatricians from all over the country, who evaluated developmental milestones and some environmental variables in healthy, normal children aged less than 6 years. A total of 3573 boys and girls aged less than six years were included. This sample was national, geographically proportionate and biased towards middle and upper social classes. The 25th, 50th, 75th and 90th centiles of age of attainment for 78 developmental milestones were estimated, applying a logistic regression model in which age was considered as the only explanatory variable. A Hosmer-Lemeshow goodness of fit test was carried out in all items, and centiles were estimated only in those items with adequate fit. 95% confidence intervals were also calculated for all centiles in all items.

Centiles were obtained in 18 items of the personal-social area, 19 of the fine motor, 18 of language, and 23 of gross-motor area. Out of these 78 items, 48 could be compared with the same items from four well known screening and diagnostic test: DDST, Denver N, BSID (Bayley), and EEDP (Chilean scale). Although in our sample some items were attained at younger ages than the tests used for comparison, no systematic trends were found. Since there are no previous data on age of attainment of developmental milestones in Argentina, results reported here may have several applications: 1) as guidelines for pediatric clinical use, 2) as an eventual screening instrument, and 3) as a unique data bank for epidemiological studies on child development.