The application of granulocyte-macrophage and granulocyte colony stimulation factors (GM-CSF and G-CSF) has been progressively increased in the treatment of patients with agranulocytosis. The aim of our study was to compare the time of neutrophil recovery in patients with severe agranulocytosis treated with G-CSF or GM-CSF and the historical control group. We have studied 6 patients with agranulocytosis treated with stimulating factors and 7 patients in historical control group. Most of the patients have been exposed to thiamazole or non-steroid antiinflammatory drugs. Our results demonstrate that patients receiving colony stimulating factor have a significantly shorter period of recovery (the mean time 8.7 +/- 1.98 days) than the historical control group (the mean time 11.0 +/- 2.24 days). We observed also a shorter time of antibiotico-therapy and hospitalization in the group of patients treated with colony stimulating factor.