Int. J. Environ. Res. Public Health 2011, 8 1522 According to a study conducted in seven Chinese cities in 2006, 29% of the nonsmoking residents and 20% of the smoking residents supported restricting smoking in restaurants and bars, and 42% of the nonsmoking residents and 24% of the smoking residents supported prohibiting smoking in these venues [12]. In January 2007, when the Beijing Health Bureau and the Chinese CDC called for voluntary smoking prohibition to thousands of restaurant owners, 86% of the respondents showed their support for prohibiting or restricting smoking in restaurants, but 52% of the respondents also expressed their concern about the potential negative influence on their revenue [12]. Supportive public attitudes are often necessary for facilitating the process of passing smoke-free legislations or regulations by local or national governments [15]. To examine the public attitudes towards banning smoking in restaurants and bars in China, a study was conducted by the Chinese CDC in 2007. It is hoped that the study results can convey key information to China and other countries which are working on creating smoke-free restaurants and bars. 2. Methods Five cities were selected for the study with consideration of both locations and local health institutes’ interests in the study: Beijing (in northern China), Xi’an (in central western China), Wuhan (in central China) and Kunming and Guiyang (both in southwest China). The total population of the five cities was 36,390,000, 6.3% of the total urban population in China in the end of 2006 [16]. A total of 814 restaurants and bars were selected in the five cities using the method described previously [17]. First, one urban district and one suburban district were selected based on convenience sampling in each city. Next, different types of restaurants and bars were selected in proportion to the numbers of these venues listed in the city’s online yellow pages, resulting in approximately 50 Chinese dining, five Chinese fast food, five Western dining, five Western fast food restaurants and 15 bars in each district. Lastly, the research team from the local CDC or an equivalent health education institute in each city invited owners to participate in the study by phone if a customer service number was available or by visiting the venues in person and asking owners to participate in the study. All owners were told that the study was interested in aggregated results rather than individual data, and that all their information would be kept confidential. Oral consent was obtained from each participating owner. Questionnaire interviews of owners from all these venues were conducted and field measurements of a SHS tracer, fine particulates matters (PM2.5), were also conducted in 404 of these venues. This convenience sampling approach was used because of the budget limit as well as logistic issues for field survey and instrumental measurements. This paper only reports the results of questionnaire interviews of owners and results of the field measurements were reported elsewhere[17]. In-person interviews of restaurant or bar owners were conducted from July to September 2007 by trained personnel in each city with a standard protocol developed by the Chinese CDC. When an owner was not available during the study period (usually owners of large restaurants or bars) the venue manager was interviewed instead after he/she contacted with the owner by phone for authorization to participate in the survey.