The aim of this A randomized controlled clinical trial is to evaluate the effects of non-nutritive sucking on the survival gastric residual volume of gavages in preterm infants. In this study 86 infants with inclusion criteria: ( age between 28-32 weeks ; weight between 750-1500 gm; clinically stable ;no medical contraindications for non-nutritive sucking, No congenital abnormalities and digestive system problems ) and the baby will excluded from the study if occures problems such as : Intraventricular hemorrhage grade 3 and 4 , Periventricular locomalacy , necrotizing enterocolitis , BPD , chronic diseases of the lung, mechanical ventilation , neonatal seizure , positive culture , meningitis , NPO baby for any reason, more than 24 hours. All infants will be randomly selected and divided into two groups. For infants who are in the first group, non-nutritive sucking with pacifier will begin since the beginning of gavages (during gavages) and will continue for 10 minutes after its (the method of gavages will be pushed in all neonates). This practice, three times a day (in the afternoon in hours 3, 5 and 7) will continue for 7 days. Infants in the second group will be gavages on routine ward’s program but they will not be received non-nutritive sucking. In both groups, after initiation of feeding, amount of gastric residual volume, as the primary outcome will be measured at 1 and 2 hours by a syringe during study days and recorded in the relative forms then compared by researcher. It is not possible to blind study.