Objective: Acinetobacter baumannii is a gram-negative, aerobic cocco- bacillus found in water and soil. It causes soft tissue infections, urinary tract infections, pneumonia, bacteremia, and meningitis. A. baumannii is a pathogen of concern due to the healthcare-associated infections it causes and limited therapeutic options. This study aims to evaluate the course of A. baumannii infections and skin colonization detected during active surveillance, causative antibiotic susceptibilities, and prognostic risk factors in the neonatal intensive care unit. Material and Methods: Demographic, clinical, and laboratory findings of the patients who were hospitalized in Erciyes University, Faculty of Medicine, Neonatal Intensive Care Unit between 2018 and 2021 and in whom A. baumannii was grown in the sterile field, wound or skin swab cultures during the active surveillance period were evaluated retrospectively. Results: Within four years, A. baumannii was detected in cultures in 103 cases. 61% (61/103) of the cases were male. Growth was observed in 82 cases, including blood (58.3%) in 60, tracheal aspirate in 14 (13.6%), urine in three (2.9%), one each in the pleural, peritoneal, and cerebrospinal fluids, and one patient in the wound culture. During the active surveillance period, skin colonization was detected in 22 cases (21.4%), while invasive disease developed in one of these cases (1/22, 4.5%). While all agents were susceptible to colistin and resistant to beta-lactams and carbapenems, only one agent was sensitive to aminoglycosides. 77.7% of the cases were premature, and 27% had an underlying disease. Bacterial co-infection was observed in 28.2% of the cases. There was no significant difference in terms of birth weight and prematurity between the groups with colonization and infection. Mortality was significantly higher in the infection group than in the colonization group (39% vs. 9.5%). In the infection group, low birth weight, small postnatal age, high procalcitonin, low platelet, high creatinine values on the first day of the treatment and following the seventh day, and low lymphocyte values on the third day of treatment were found to be associated with mortality. Gender, prematurity, concomitant diseases, and C-reactive protein values were not associated with mortality in the infection group. Conclusion: A. baumannii infections cause high mortality in newborns. Although the transition rate from colonization to infection is low, cross-contamination within the unit should be prevented as much as possible due to the high infection mortality. Vascular catheters and TPN should be stopped as soon as possible. Monitoring acute kidney injury, procalcitonin, and absolute lymphocyte and platelet values in the follow- up of infected cases can provide clinicians with important information about prognosis.