BACKGROUND: Most previous studies of the family doctor contract services (FDCS) evaluated its quality by using residents' signing rates, awareness, and satisfaction. We hypothesize that renewal willingness could be another important indicator to examine the quality of FDCS. OBJECTIVE: To measure residents' willingness to maintain contracts with family doctors and examine the influencing factors. DESIGN: Cross-sectional study. PARTICIPANTS: 11,250 residents in 31 provincial administrative regions across China. MAIN METHODS: A multistage stratified random sampling method was used to recruit participants. Univariate analysis, mixed-effect regression model analysis, and stepwise multivariate logistic regression analysis were performed to determine the influencing factors of residents' willingness to maintain contracts with family doctors. KEY RESULTS: About 71.3% participants who contracted with and received healthcare services from family doctors were willing to maintain contracts with family doctors in China. Residents registering as local households (