Objective:To evaluate the impact of suggested change of stillbirth definition of newborns 500-999 grams on the total perinatal mortality in the Czech Republic. Comparing the database of aggregated national data on stillborn babies 500-999 grams and the database of individual data on miscarriages of the same birth weight we found that the number of stillborn babies in 2003 was 15% smaller than number of miscarriages (151 versus 178).