This study aimed to examine characteristics of non-member of the Japan Dietetic Association (JDA) and non-participants of seminars who were held by the JDA. In November to December 2018, a cross-sectional self-administered internet survey was conducted. Data from 15,133 participants requiring a qualification for employment were analyzed. The items of a questionnaire included demographic characteristics, admission to the JDA, reasons for non-membership of the JDA, a situation of participations in seminars held by the JDA, and reasons for non-participation in seminars. Non-members of the JDA were younger and included more people who had a qualification of only dietitian and a graduate of university, employed irregularly, had lower length of working and annual income, worked at schools, facilities making school lunch, nurseries, and kindergartens than members of the JDA. The reasons for non-members of JDA were membership high fees, a busy life, and not to know the activities of the JDA. The characteristics of non-participants of seminars were similar with non-membership of the JDA. The reasons for non-participants of seminars were not to match their schedules. Those who were non-members of the JDA and non-participants in seminars were common in age, irregularly employed, length of working, annual income, and their workplace.