The Effect of Nursing Interventions on The Stress Levels of Mothers Whose Premature Infants are in Neonatal Intensive Care Unit This quasi-experimental study was carried out to determine the effect of nursing interventions on the stress levels of premature infants' mothers. The population of the study consisted of the mothers of premature infants who were hospitalized in the Neonatal Intensive Care Unit of Trakya University Medical Faculty Hospital located in the city center of Edirne. A total of 62 mothers, 31 controls and 31 interventions, were included in research sample. In data collection, Parent Stress Scale: Neonatal Intensive Care Form, Mother Information Form Neonatal Description From, prepared by the researcher, were used. Date collection forms were used in control and intervention groups two times, once as pretest and once as posttest. Data were analyzed through a computer program and p<.05 was determined as significant. Mothers in the control group received the routine care in the clinic. Mothers in the intervention group received instructional and supportive nursing interventions including point-of-care training, establishing skin-to-skin contact, kangaroo care, education seminar, establishing interaction with other premature infants' mothers and giving training manual. There was no significant difference between the control and intervention groups in terms of socio-demographics, family and obstetric characteristics, and the characteristics of newborn infants, and both groups were 16 similar (p>.05). In the pre-intervention pre-tests, when the stress levels of the mothers in the control and intervention groups were compared, no significant difference was found between the two groups (p>.05). In the posttests performed after the intervention, it was determined that the stress levels of the mothers in the intervention group was significantly lower than the stress levels of the mothers in the control group (p<.01). In this study, it was determined that educational and supportive nursing interventions applied to mothers of premature infants, who were hospitalized in the neonatal intensive care unit, decreased the stress level of mothers. It was recommended that mothers of the premature infants should be trained and supported by the neonatal intensive care nurses. Key Words: Newborn İntensive Care Unit, Premature baby, Mother, Nurse, Stress