It was aimed to determine the effect of parental participation on newborn comfort during diaper care practice in preterm infants.

H1: Parental participation during infant diaper care practice in preterm infants has an effect on newborn comfort.

H2: There is a difference in the effect of parent diaper care practice and the participation of the mother or father on newborn comfort in preterm infants.

H3: There is a difference between the stress levels of parents before the application of infant diaper care in preterm infants.

The expectation of all parents is to have a healthy baby at the end of the pregnancy. However, newborns being born unexpectedly early and being admitted to the neonatal intensive care unit is a stressful situation for both newborns and parents. During this process, parents of preterm infants experience anxiety, loss of control, fear of the future, depression, role change and concerns about the improvement of the baby's condition. It is important for parents to actively participate in care within the framework of family-centered care practices in order to reduce the newborn's stress level, increase its comfort and improve its environment and to increase the families' ability to cope with this situation.Infant care, which is repeated many times a day in the Neonatal Intensive Care Unit, is one of the care practices that include tactile stimuli. Studies have observed that preterm infants' stress increases during diaper changes. For this reason, it is important to plan the necessary invasive practices to increase comfort during diaper changes, to include parental participation in these procedures, and to determine the effect of these interventions on the infants' comfort and to include them in the literature.

Inclusion Criteria:

• Infants whose gestational age is between ≥34 weeks and ≤36+6 weeks at the time of application
• Infants with stable health conditions

Exclusion Criteria:

• Intubated
• Those with very low and extremely low birth weight at the time of procedure
• Having a chronic disease
• Those with congenital anomalies
• Having undergone a surgical procedure
• Having neurological symptoms
• Receiving oxygen support
• Diagnosed with sepsis
• Sedated
• A pharmacological analgesic method was used four hours before.
• Parents who do not want to participate in care