BACKGROUND: The Quality and Outcomes Framework, a financial incentive scheme for general practitioners in the UK, seems to have improved the quality of primary care and reduced inequalities in primary care delivery. It remains unclear, however, whether higher-quality primary care improves health outcomes or reduces health inequalities. METHODS: We conducted a cross-sectional study examining the association between quality of cardiovascular care and coronary heart disease (CHD) outcomes in 1531 general practices in London. We calculated CHD quality achievement scores (ranging from 0 to 100) for each practice using the 2006-2007 data from the Quality and Outcomes Framework. We used weighted linear regression models to assess the practice-level association between the CHD quality score and CHD admissions and deaths. FINDINGS: Overall, practices with higher CHD quality achievement scores had better CHD outcomes. Each one point increase in the CHD quality achievement score was associated with 4.28 (95% CI 1.19 to 7.38; p=0.007) fewer admissions per 100,000 for practices serving highly deprived populations and 2.11 (95% CI 0.68 to 3.55; p=0.004) fewer admissions per 100 000 for practices serving populations of average deprivation. There was no association between the CHD quality achievement score and the CHD admissions for practices serving affluent populations (p=0.906). We observed a similar deprivation-dependent gradient between quality achievement and CHD deaths. INTERPRETATION: High-quality primary care is associated with improved health outcomes. This association is strongest in deprived areas, suggesting that high-quality primary care may play an important role in reducing health inequalities.