Despite the increasing use of patient satisfaction data for compensation and comparison of performance, low response rate and potential bias of the respondents pose a significant threat to validity of the data. The demographic profiles of respondents and nonrespondents to a patient satisfaction survey in the ambulatory care setting were compared to explore the impact of nonresponse bias.Patient satisfaction survey data were collected from October through December 2010 for outpatient facilities at a large academic medical center. The association between respondent characteristics and satisfaction ratings on three dimensions of the clinical care process—(1) interpersonal communication (clarity of language), (2) service delivery (overall care during visit), and (3) likelihood of recommending practice to others—were assessed with bivariate and multivariate linear regression. Weighted analyses were performed to examine the impact of nonresponse.Surveys were mailed to 15,549 patients, of which 4,952 (32%) were returned. Respondents had greater proportions of elderly, female, and English speakers. Bivariate analyses showed significant difference in satisfaction ratings by age, language, and insurance type. Multivariate regression analysis showed significant confounding across variables. On the basis of the calculated weighted means, mean satisfaction ratings were discrepant for language and age; however, the overall satisfaction ratings for each dimension were minimally affected.Nonresponse rates and satisfaction ratings differed by age, language, and insurance type. However, if it is assumed that nonrespondents within these demographic groups have similar satisfaction ratings as respondents, then nonresponse levels appear to have minimal effects on overall satisfaction ratings.