Metamizole sodium continues to be used extensively as an analgesic in Poland. This study was the first undertaken to quantify the incidence of agranulocytosis associated with metamizole sodium in Poland, and to compare the findings with those from other countries. Based on data obtained retrospectively from medical records covering the period 1997-2001 in six haematology centres representative of Poland as a whole, the crude estimate obtained was a rate of 0.2 cases per million person-days of use. This is the same order of magnitude as the value from an epidemiological study covering several countries (0.3-4.0).