Objective: This study examined the posttraumatic stress of parents with a newborn in the neonatal intensive care unit (NICU), the differences between their posttraumatic stressors, the factors that affect posttraumatic stress, and the experiences of parents. Methods: The parents of 66 newborn infants (66 mothers and 66 fathers) in the NICU were the sampling group, and a descriptive design was used. The sociodemographic traits of parents were identified using a data collection form, and posttraumatic stress experiences of parents were identified by using the Impact of Events Scale-Revised (IES-R). Analysis of variance and t-test for two independent groups were used for the comparisons, and a chi-square test was used. Results: The mean of the total scale scores (mothers 43.61 +/- 14.98; fathers 36.26 +/- 17.01), mean of the intrusion scores (mothers 18.17 +/- 6.25; fathers 15.13 +/- 7.14), and mean of the avoidance scores (mothers 11.21 +/- 4.94; fathers 9.17 +/- 5.17) were high. When the scores for the IES-R and subscale scores of parents were compared, mothers scored 20 higher than fathers, a statistically significant difference. When the cut-off point was 30, 81.8% of mothers and 66.7% of fathers experienced posttraumatic stress. Conclusion: In light of these findings, it is recommended that health professionals monitor all parents with a newborn in the NICU for symptoms of posttraumatic stress and that parents are informed about their newborns.