ImportanceIt is important to assess how the COVID-19 pandemic was adversely associated with patients’ care experiences.ObjectiveTo describe differences in 2020 to 2021 patient experiences from what would have been expected from prepandemic (2018-2019) trends and assess correlates of changes across hospitals.Design, Setting, and ParticipantsThis cohort study compared 2020 to 2021 data with 2018 to 2019 data from 3 900 887 HCAHPS respondents discharged from 3381 HCAHPS-participating US hospitals. The data were analyzed from 2022 to 2023.Main Outcomes and MeasuresThe primary outcome was an HCAHPS summary score (HCAHPS-SS), which averaged 10 HCAHPS measures. The primary analysis estimated whether HCAHPS scores from patients discharged from 2020 to 2021 differed from scores that would be expected based on quarterly and linear trends from 2018 to 2019 discharges. Secondary analyses stratified hospitals by prepandemic overall star ratings and staffing levels.ResultsOf the 3 900 887 HCAHPS 2020 to 2021 respondents, 59% were age 65 years or older, and 35% (11%) were in the surgical (maternity) service lines. Compared with trends expected based on prepandemic (2018-2019) data, HCAHPS-SS was 1.2 percentage points (pp) lower for quarter (Q) 2/2020 discharges and −1.9 to −2.0 pp for Q3/2020 to Q1/2021, which then declined to −3.6 pp by Q4/2021. The most affected measures (Q4/2021) were staff responsiveness (−5.6 pp) and cleanliness (−4.9 pp); the least affected were discharge information (−1.6 pp) and quietness (−1.8 pp). Overall rating and hospital recommendation measures initially exhibited smaller-than-average decreases, but then fell as much as the more specific experience measures by Q2/2021. Quietness did not decline until Q2/2021. The HCAHPS-SS fell most for hospitals with the lowest prepandemic staffing levels; hospitals with bottom-quartile staffing showed the largest decrements, whereas top-quartile hospitals showed smaller decrements in most quarters. Hospitals with better overall prepandemic quality showed consistently smaller HCAHPS-SS drops, with effects for 5-star hospitals about 25% smaller than for 1-star and 2-star hospitals.Conclusions and RelevanceThe results of this cohort study of HCAHPS-participating hospitals found that patient experience scores declined during 2020 to 2021. By Q4/2021, the HCAHPS-SS was 3.6 pp lower than would have been expected, a medium effect size. The most affected measures (staff responsiveness and cleanliness) showed large effect sizes, possibly reflecting high illness-associated hospital workforce absenteeism. Hospitals that were lower performing and less staffed prepandemic may have been less resilient to reduced staff availability and other pandemic-associated challenges. However, by Q4/2021, even prepandemic high-performing hospitals had similar declines.