BACKGROUND: There has been growing interest in using real-world evidence (RWE) for health technology assessment (HTA) in the United States. The Institute for Clinical and Economic Review (ICER) is an independent U.S.-based HTA organization that focuses primarily on pharmaceuticals. RWE is used to inform ICER's scoping and comparative clinical effectiveness (CCE) assessments, but the extent to which it is used has not been quantified. OBJECTIVE: To systematically evaluate use of RWE in the scoping and CCE assessment sections of the ICER HTA reports on pharmaceuticals. METHODS: We reviewed all ICER reports of pharmaceuticals published between January 2014 and June 2019. We examined the average number of instances and the proportion of RWE use in the scoping documents to inform the population, intervention, comparator, outcome, setting, or timing (PICOTS) elements of the appraisal. We also examined the average number of instances and the proportion of RWE use in the CCE assessments to inform effectiveness, safety, or treatment patterns. Finally, we evaluated use of RWE in clinical guidelines that were cited in the CCE assessments. RESULTS: In ICER scoping documents, the mean (SD) number of instances of RWE use was 3.8 (3.7) per document (55% for outcomes, 20% for population, 14% for comparator, 11% for intervention, and 0% for timing and setting). In ICER CCE assessments, the mean (SD) number of instances per assessment was 0.7 (0.5) per drug (53% for effectiveness, 44% for safety, and 3% for treatment patterns). In clinical guidelines used in ICER reports, the mean (SD) number of instances of RWE use was 1.6 (2.3) per drug per guideline (41% for effectiveness, 30% for safety, and 29% for treatment patterns). CONCLUSIONS: RWE was frequently used in the ICER scoping process, particularly to inform selection of outcomes. RWE was used infrequently in ICER CCE assessments, while more often used to inform effectiveness, safety, and treatment patterns in relevant clinical guidelines. There are opportunities to increase the use of RWE in U.S. HTA processes. DISCLOSURES: This study was supported by the Health Tech Fund, University of Washington School of Pharmacy, which was created through unrestricted support from several health care industry companies. Veenstra and Carlson report grant support from the Institute for Clinical and Economic Review outside the submitted work. Carlson reports personal fees from Bayer, Allergan, and Galderma outside the submitted work. Jiao, Lee, and Devine report no support outside the submitted work.