Argentine growth references have been widely used by paediatricians in the country for the last 20 years. Two main difficulties were detected during this period: the lack of data on breast-fed children in the first months of age, and problems in the calculation of "z" scores. On these basis, local data on weight and height during the first two years of life were replaced by data from the longitudinal international study recently carried out by WHO. L, M and S values were obtained from the original percentile data for ages 2 to maturity, and smoothed with cubic splines. Selected percentiles for weight and height from birth to maturity were then re-calculated using LMS values. Charts were designed in two formats: birth to maturity and birth to 6.0 years. Now, users can calculate "z" scores automatically at the new site provided by the Department of Growth and Development, Hospital Garrahan, which enables the use of the LMS growth programme. We have also incorporated into the new charts, percentiles of the age of attaining menarche and Tanner s stage II of breast, genitalia and pubic hair for Argentine children. We think the new references represent an improvement in the assessment of growth in our country.