DISCLAIMER: In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. PURPOSE: The objective of this study was to implement a standardized process across health systems to determine the prevalence and clinical relevance of prescribing errors intercepted by pharmacists. METHODS: This prospective, multicenter, observational study was conducted across 11 hospitals. Pharmacist-intercepted prescribing errors were collected during inpatient order verification over 6 consecutive weeks utilizing a standardized documentation process. The potential harm of each error was evaluated using a modified National Coordinating Council for Medication Error Reporting and Prevention (NCC-MERP) index with physician validation, and errors were stratified into those with potentially low, serious, or life-threatening harm. Endpoints included the median error rate per 1,000 patient days, error type, and potential harm with correlating cost avoidance. RESULTS: Pharmacists intervened on 7,187 errors, resulting in a mean error rate of 39 errors per 1,000 patient days. Among the errors, 46.6% (n = 3,349) were determined to have potentially serious consequences and 2.4% (n = 175) could have been life-threatening if not intercepted. This equates to $874,000 in avoided cost. The top 3 error types occurring with the highest frequency were "wrong dose/rate/frequency" (n = 2,298, 32.0%), "duplicate therapy" (n = 1,431, 19.9%), and "wrong timing" (n = 960, 13.4%). "Wrong dose/rate/frequency" (n = 49, 28%), "duplicate therapy" (n = 26, 14.9%), and "drug-disease interaction" (n = 24, 13.7%) errors occurred with the highest frequency among errors with potential for life-threatening harm. "Wrong dose/rate/frequency" (n = 1,028, 30.7%), "wrong timing" (n = 573, 17.1%), and "duplicate therapy" (n = 482, 14.4%) errors occurred with the highest frequency among errors with potentially serious harm. CONCLUSION: Documentation of pharmacist intervention on prescribing errors via a standardized process creates a platform for multicenter analysis of prescribing error trends and an opportunity for development of system-wide solutions to reduce potential harm from prescribing errors.