Objectives Posttraumatic growth (PTG) refers to a positive psychological transformation experienced as a result of struggling with a major life crisis or traumatic event. In recent times, PTG has been used as a form of psychological support for those who have experienced trauma. In this study, we classified the free descriptions of PTG in Fukushima residents who experienced the Great East Japan Earthquake (GEJE). We examined the relationship between basic characteristics and PTG clusters, and between "recovery from radiation anxiety" and PTG clusters.Methods A mail survey was conducted in August 2016 among 2,000 Fukushima residents, aged 20-79 years. We asked the participants for a free description of the specific content of their PTG. We also asked about their age, gender, and education, as well as about radiation anxiety immediately after the GEJE and at the time of the survey. Participants were divided into the following groups: "no anxiety," "recovered from anxiety," and "unrecovered from anxiety". The PTG free descriptions were classified into eight categories, including five dimensions based on the Posttraumatic Growth Inventory (Tedeschi & Calhoun, 1996) ("relating to others," "new possibilities," "personal strength," "spiritual change," and "appreciation of life") and three categories created according to Nishino et al. (2013) ("increased awareness of disaster prevention," "renewed recognition of nuclear-related issues," and "critical examination of information from authorities").Results Of the 916 collected responses, data from 786 responses with no missing values were analyzed. Among women and young people, the proportion of those who answered "relating to others" and "appreciation of life" was high. For those with higher education, the proportion of those who answered "relating to others," "renewed recognition of nuclear issues," "critical examination of information from authorities," "personal strength," "spiritual change," and "appreciation of life" was high. In the "recovered from anxiety" group, the proportion of those who answered "renewed recognition of nuclear issues" was high.Conclusion In assessing PTG, women and young people were more likely to report that they felt closely connected to family or friends, as well as to the community, and that they were grateful for their daily lives. Those with higher education tended to recognize that they have come to critically examine information provided by the national government, electric power companies, and national newspapers; they felt mental strength and growth after the earthquake. Those who recovered from radiation anxiety were more likely to report forming a heightened awareness of issues relating to nuclear power plants and energy.