BACKGROUND: The benefits of pay-for-performance schemes in improving the quality of care remain uncertain. There is little information on the effect of removing incentives from existing pay-for-performance schemes. METHODS: We conducted interrupted time-series analyses of electronic medical record (EMR) data from 2010 to 2017 for 12 quality-of-care indicators in the United Kingdom's Quality and Outcomes Framework for which financial incentives were removed in 2014 and 6 indicators for which incentives were maintained. We estimated the effects of removing incentives on changes in performance on quality-of-care measures. RESULTS: Complete longitudinal data were available for 2819 English primary care practices with more than 20 million registered patients. There were immediate reductions in documented quality of care for all 12 indicators in the first year after the removal of financial incentives. Reductions were greatest for indicators related to health advice, with a reduction of 62.3 percentage points (95% confidence interval [CI], -65.6 to -59.0) in EMR documentation of lifestyle counseling for patients with hypertension. Changes were smaller for indicators involving clinical actions that automatically update the EMR, such as laboratory testing, with a reduction of 10.7 percentage points (95% CI, -13.6 to -7.8) in control of cholesterol in patients with coronary heart disease and 12.1 percentage points (95% CI, -13.6 to -10.6) for thyroid-function testing in patients with hypothyroidism. There was little change in performance on the 6 quality measures for which incentives were maintained. CONCLUSIONS: Removal of financial incentives was associated with an immediate decline in performance on quality measures. In part, the decline probably reflected changes in EMR documentation, but declines on measures involving laboratory testing suggest that incentive removal also changed the care delivered.