Background and Design.- We aimed to search the impacts of granulocyte colony stimulating factor (rhG-CSF), on antibiotherapy clinical and radiologic recovery, in a group of patients without any previous lung pathology but ventilated because of acute respiratory failure, in whom rhG-CSF used as the treatment of nosocomial pneumonia (VAP). The first group (n=16) received 5 mgr/kg/day subcutaneous rhG-CSF as a supplement to antibiotherapy while in the second group (n=13) the sole treatment was antibiotherapy. For each patient studied, the chart is reviewed at the first day of mechanical ventilation and for 8 days after VAP for the following parameters: erythrocyte, leukocyte, granulocyte and platelet counts; SGOT, SGPT, blood urea, creatine; microbiological analyses of transtracheal aspirate, hemocultures and infiltrations shown on chest x-ray, body temperature follow-up hourly. APACHE II scores of patients are also recorded. Statistical comparisons among groups are performed with Mann-Whitney U test.Results.- The groups did not differ significantly for erythrocyte, platelet counts and blood urea, creatine, SGOT, SGPT (p>0.05). The difference is found to be much more significant according to leukocyte and granulocyte counts in rhG-CSF group, when compared to control group(p<0.001). Comparison of the mean values of body temperature, of two groups, appeared to be statistically significant on behalf of rhG-CSF group (p<0,05).Conclusion.- We conclude, combination of antibacterial agents and rhG-CSF may be beneficial for the treatment of VAP.* Anahtar Kelimeler: Mekanik ventilasyon, Nosokomiyal pnömoni, Granülosit-koloni stimüle edici faktör, Nötrofil* Key Words: Mechanical ventilation, Nosocomial pneumonia, Ventilation associated pneumonia, Granulocyte-colony stimulating factor, Neutrophil