Background As population aging progresses, volunteers in health field are expected to play a key role in health promotion and disease prevention, which may improve community residents' health and well-being and at the same time help slow the growth of healthcare cost. The objective of this study is to examine the effects of self-oriented motives and altruistic motives as explanatory factors for Japanese Community Health Workers (CHWs)' desire to continue their service. Unraveling the relative effects of these two types of motivation on CHW retention may lead to policy and practical implications for recruiting, training, and supporting CHWs in Japan. Haddad (2007) observed that citizens in Japan generally have a sense of governmental and individual responsibility for dealing with social problems. Applying these insights to CHWs, we hypothesize that altruistic motives have more potent influence on volunteers' willingness to continue to serve than self-oriented motives. Methods Three cities in Shiga prefecture, Japan agreed to participate in the study. Anonymous, self-administered questionnaire was mailed to all CHWs who work in the three communities. The survey data were collected in March and April, 2013. A total of 417 questionnaires were mailed to CHWs, of which 346 were completed and returned (response rate 83.0%). Nine questionnaires missing response to the question concerning willingness to continue serving were removed from the analysis. The final analysis used 337 questionnaires (effective response rate 80.8%). Results One hundred ninety-nine (59.1%) of the respondents answered the question about willingness to continue CHW affirmatively, and 138 (40.9%) negatively. Controlling for other relevant factors, those with self-oriented motives in serving as CHWs were more likely to state they are willing to continue to serve (OR:1.54, confidence interval 1.00-2.37) than those without such motives. Those with altruistic motives were also more likely to say they want to continue their service (OR 1.56, confidence interval 1.08-2.27) than those without such motives. Contrary to our hypothesis, the two motives, altruistic and self-oriented, were shown to have nearly equal degree of influence on respondents' willingness to continue serving as CHWs. Conclusion One practical implication of the research is that learning more about the twin motives, self-oriented and altruistic, of volunteers and tailoring the content of CHW training by municipal health professionals to address those motives may be beneficial.