This book is based the study performed as a quasi-experimental clinical trial. It was conducted on 40 premature infants who were hospitalized in NICU and had inclusion criteria for 4 continous days. Sampling lasted for 4 months and was done along three consecutive feeding times using NG tube. Non-nutritive sucking started 5 minutes before feeding until 5 minutes after feeding, first time with mother's finger, second time with pacifier and third time without any interventions. Infants' heart rate and oxygen saturation were measured 5 minutes before feeding, 1 minutes after starting feeding and 5 minutes after ending feeding. Based on the results of this research, oral stimulation can have good effect on physiological parameters. Stability of these parameters indicates health rate of infant. This stability is necessary for discharging infant. On the other hand, presence of mother at the bedside of her infant helps the infant to get well soon. Considering these factors, oral stimulation can reduce physical and mental problems of infants and their families as well as reduce the financial burden on the family and society.