Thoracentesis is an invasive procedure known to result in complications. Procedure skills should be taught and evaluated more effectively to improve health care quality. Validated checklists are central to teaching and assessing procedural skills. The results of the first step of the validation of a thoracentesis checklist are described. A comprehensive literature review of articles published on thoracentesis did not yield a validated checklist. A modified Delphi technique, involving a panel of 8 interdisciplinary, interinstitutional experts, was used to develop a thoracentesis checklist. The internal consistency coefficient using Cronbach's α was.94. Developing the 23-item thoracentesis checklist for teaching and assessing thoracentesis 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. © 2013 by the American College of Medical Quality.