This study lays its purpose on finding out differences in job satisfaction according to working environments among workers at mental sanatoria and factors affecting their job satisfaction. As a result, the following findings have been derived. First, in terms of general working environments, the majority of workers at mental sanatoria were employed through open recruitment (81.5%) for regular job positions, males and females in their 30s constituted the majority (44%), as religion Christians were 52.4%, as educational attainment, workers with college graduation and higher were 43.7%, and the majority of males and females (73.8%) were found to be married. As professional certifications, the certificate of social workers were most as 62.2%, and the amount of the annual salary was between 20,000 thousand won and 30,000 thousand won (66.2%). As job tenure, people who have been working for under 7 years were most (63.5%), working hours a day of 8 hours and less were 47.2% thanks to the 40-hour a week system, and it was found that more than the half of the workers were involved in overtime work (51.4%). As the vacation system workers in the Jeonnam area answered that they could use their vacation freely (57.7%), while 82.7% and 78.5% workers in the Gwangju and the Jeonbuk areas respectively answered that they could use it freely, indicating the regional difference. Second, in terms of differences in the actual status of working environments, when taking a look at types of the employment contract and differences in former careers, employment contracts, recruitment paths, the number of working days, monthly leaves, annual leaves, and parental leaves differed according to both institutions and regions, former careers differed according to regions, and remedial training and the number of working hours differed according to institutions. Parental leaves were found to significantly differ by gender ( χ 2=8.834, p<.05), institution ( χ 2=146.093, p<.01), and region ( χ 2=51.318, p<.01). Third, looking at differences in job satisfaction by factor according to working environments, it showed very significant differences by self esteem (t=3.639, p<.01), self efficacy (t=3.189, p<.01), salary (t=-11.910, p<.01), promotion (t=-13.932, p<.01), and colleagues (t=5.982, p<.01), indicating that the significant correlation between levels of job satisfaction and these factors. Fourth, as factors affecting job satisfaction, colleagues and job were found to be the most influential factors through chi-square test of homogeneity, while the number of working years, self esteem, and self efficacy were found to have few effects on job satisfaction. Putting these results together, we can understand that factors differing by gender, region, and institution have major effects on job satisfaction among workers. Accordingly in order to enhance efficiency in the management of mental sanatoria, individual workers' psychological and emotional status should be improved and institutions should make more positive efforts to do it.