AbstractIn this retrospective analysis, the Newborn Life Support (NLS) test scenario performance of participants of the Dutch Neonatal Advanced Life Support (NALS) course was assessed. Characteristics of participants and total amount of failures were collected. Failures were subdivided in (1) errors of omission; (2) errors of commission; and (3) unspecified if data was missing. Pearson’s chi-squared test was used to assess differences between participant groups. In total, 23 out of 86 participants (27%) failed their NLS test scenario. Life support course instructors in general (20/21) passed their test scenario more often compared to other participants (43/65) (p = 0.008). In total 110 fail items were recorded; the most common errors being not assessing heart rate (error of omission) (n = 47) and inadequate performance of airway management (error of commission) (n = 24).Conclusion: A substantial part of NALS participants failed their NLS test scenario. Errors of omission could be reduced by the availability of a checklist/NLS algorithm. Life support course instructors possibly make less errors of commission due to retention of skills by teaching these skills at least twice a year. Therefore, our study suggests that neonatal basic life support skills should be retained by local assurance of training programmes. What is Known:• Retention of skills after life support courses decreases after three months.• Adherence to newborn life support guidelines is suboptimal. What is New:• NLS performance is suboptimal in participants for advanced neonatal life support.• Most common failures are not assessing heart rate and inadequate airway management.