Background: The aim of this study was to design and validate a new checklist and standardized scenario for assessing providers’ performance during Newborn Life Support (NLS). Methods: We invited twelve experts in Neonatology to take part in a three-step Delphi process. They rated the importance of each item of a newly designed assessment tool to evaluate participants’ performance during Newborn Life Support independently on a numeric rating scale from 1 to 5 (1 = lowest; 5 = highest) and were able to give additional comments. All items achieving a mean rating below four after the third round were deleted. For the reliability of the checklist, we calculated interrater reliability. Results: Using a standardized Delphi process, we revised the initial checklist according to the experts’ ratings and comments. The final assessment tool includes 38 items covering all relevant steps during NLS. The mean expert rating of all items was 4.40. Interrater reliability showed substantial agreement between the two raters in the first draft (κ = 0.80) as well as in the final draft of the checklist (κ = 0.73). Conclusion: We designed a feasible assessment tool for evaluating performance during NLS. We proved the checklist to be valid and reasonable using a Delphi validation process and calculating interrater reliability.