In a randomized clinical trial , admitted premature neonates to NICU of Shahid Sadoughi Hospital , Yazd, Iran will be enrolled and randomly assigned to two groups. Laboratory tests including CBC, CRP, blood culture and urine culture will be performed for all participants at baseline and at the end of fourteenth day of the study. Both groups will be treated with the same antibiotics. In group I, subcutaneous GCSF in dosage of 10 μg / kg / day will be given for 5 consecutive days and the other group will receive normal saline subcutaneously. The neonates will be followed up for 14 days and respiratory status (oxygen dependency or need to mechanical ventilation), amount of tolerated feeding , occurrence of abdominal distension, side effects of injection, fever occurrence and its duration, thrombocytopenia, weight gain, confirmed documented sepsis by cultures and mortality will be evaluated in both groups.