In parallel to market-like reforms in Swedish primary care, the gathering and compilation of comparative information about providers, for example through survey tools, has been improved. Such information is increasingly being used to guide individuals' choice of provider and payers' assessments of provider performance, often without critically reflecting about underlying factors affecting the results. The purpose of this study was to analyze variation in patient satisfaction, with respect to organizational and structural factors, including the mix of registered individuals, among primary care providers, based on information from a national patient survey in primary care and register data in three Swedish county councils. Systematic variation in patient satisfaction was found with respect to both organizational and structural factors, including characteristics of registered individuals. Smaller practices and practices where a high proportion of all visits were with a doctor were associated with higher patient satisfaction. Also practices where registered individuals had a low level of social deprivation and a high overall illness on average were associated with higher patient satisfaction. Factors that are of relevance for how well providers perform according to patient surveys are more or less possible to control for providers. This adds to the complexity for the use of such information by individuals and payers to assess provider performance.