Many anthropometric reference data for children are based on studies conducted up to 40 years ago. We assessed height and weight distribution of a population of German primary school children and compared the results with national and international reference data. In February 1998 weight and height were measured in 427 first grade school children (195 boys, 232 girls) aged 6 to 7 years who participated in the family intervention trial Erlangen. Compared to studies in the 1980s, weight showed a marked but height only a minimal increase. Mean weight-for-height is similar to previously published reference data, but upper percentile values are much higher. Mean weight-for-height and the proportion of overweight children are similar for children of German and of foreign origin. We conclude that overweight and obesity have clearly increased in primary school children in recent years.