Radial arterial line placement is an invasive procedure that may result in complications. Validated checklists are central to teaching and assessing procedural skills and may result in improved health care quality. The results of the first step of the validation of a radial arterial line placement checklist are described. A comprehensive literature review of articles published on radial arterial line placement did not yield a checklist validated by the Delphi method. A modified Delphi technique, involving a panel of 9 interdisciplinary, interinstitutional experts, was used to develop a radial arterial line placement checklist. The internal consistency coefficient using Cronbach α was .99. Developing a 22-item checklist for teaching and assessing radial arterial line placement is the first step in the validation process. For this checklist to become further validated, it should be implemented and studied in the simulation and clinical environments.