The involvement of private for-profit (FP) and not-for-profit (NFP) providers in the otherwise public delivery of welfare services is gradually changing the Nordic welfare state towards a more market-oriented mode of service delivery. This article examines the relationship between ownership and quality of care in public and private FP and NFP nursing homes in Denmark. The analysis draws on original survey data and administrative registry data (quality inspection reports) for the full population of almost 1000 nursing homes in Denmark. Quality is measured in terms of structural quality, process quality and outcome quality. We find that public nursing homes have a higher structural quality (in terms of, for instance, staffing), while FP providers perform better in terms of process quality (e.g. in the form of individualised care). NFP providers perform well in terms of structural criteria such as employment of full-time staff and receive fewer critical comments in the inspection reports. However, the results depend to some extent upon the method of data collection, which underlines the benefits of using multiple data sources to examine the relationship between ownership and the quality of care.