In early 1979 Robert B. Cumming recognized the growing need for risk researchers and practitioners to publish their work in a dedicated professional journal. This led to the formation of an organization to support such a journal, with the Certificate of Incorporation for the Society for Risk Analysis (SRA) made official on August 28, 1980. The first issue of Risk Analysis: An International Journal appeared in March 1981. This article reviews the history of the SRA's first 25 years. It reviews the SRA's formation and growth, provides analyses of its major products (the journal, newsletter, conferences, and meetings), and discusses its impact. This article relies on published literature and a history of the SRA's first 20 years written by two of the authors. This history covers the SRA's many successes, which demonstrate the strength and vitality of the organization and provide optimism for its future. These successes include this journal, which published over 2,150 papers between March 1981 and this December 2005 issue. The successes also include its stable membership of approximately 2,000 members from 43 countries, well-attended annual meetings, and increasing support for true international growth as demonstrated by international risk forums like the World Congress on Risk held in Brussels in June 2003. Similarly, the history also covers the SRA's challenges and difficulties, with the recognition that these provide both an important context about the organization and the opportunity to learn from past experiences. These include the challenges associated with spin-off organizations that decreased the SRA membership in some disciplinary areas, notably in engineering and exposure assessment. This history also includes quantitative analyses of the contents of the first 25 years of Risk Analysis: An International Journal. The results show significant growth in the number of articles published each year, starting with approximately 30 articles published in the first few years to over 120 articles per year now. They also show a relatively even distribution of articles in the life, physical, and social sciences, which demonstrate the sustained commitment of the SRA and the journal to support interdisciplinary risk-related research. The SRA organizational structure currently includes two sections (SRA-Europe and SRA-Japan), 22 Chapters, and nine Specialty Groups, and the structure remains somewhat in flux. We present this history in five sections that cover major themes: (1) SRA formation, (2) membership and organization, (3) publications, (4) meetings, and (5) thematic issues. Like any organization of its size, the SRA boasts a long and diverse history, and no article can possibly capture it all. We hope that in documenting the first 25 years, we strengthen the SRA by providing some perspective on its roots and a rigorous quantitative analysis of some of its products.