GOALS: We aimed to develop and validate a patient-reported experience measure for gastrointestinal (GI) endoscopy, the Comprehensive Endoscopy Satisfaction Tool that captures relevant domains that influence the patient's experience and identify factors that shape satisfaction. BACKGROUND: Patient-reported experience measures are used to capture specific quality aspects of health care services. GI endoscopic services are high-volume services, and there is a lack of specific, validated instruments to capture various domains that shape the patients' experience with routine clinical endoscopic services. STUDY: After an environmental scan and structured literature review, focus groups with patients were conducted to identify relevant factors influencing the patient experience with GI endoscopic services. After an initial validation in 101 patients undergoing routine GI endoscopies, the instrument was tested in 7800 patients. In addition, the influence of sociodemographic factors on global satisfaction was explored. RESULTS: The final version included 26 specific items plus 4 global ratings for preprocedure, experience on day of procedure, postprocedure care, and infrastructure. In addition, a global rating of the overall experience was included. Patient satisfaction was significantly higher in older patients (P<0.001) but not influenced by gender, nationality, marital status, education, or employment status. Interestingly, during periods of coronavirus disease-19-related service interruptions, the Net Promoter Score was significantly reduced (P<0.0001) providing evidence for the responsiveness of the instrument. CONCLUSIONS: The Comprehensive Endoscopy Satisfaction Tool is a valid measure for the patient experience with the various components of endoscopic services, allows for the identification of domains that impact on the patient experience and is a practical tool to compare patient satisfaction over time and across facilities.