Objective: We aimed to indicate the direction of developing first comprehensive guidelines for adult-onset cancer survivors in Japan, according to the circumstances of the Japanese healthcare system, by establishing consensus among various stakeholders in Japan. Methods: Purposive sampling was used to recruit a panel of experts in oncology clinical practice, nursing, health science, epidemiology, and patient advocacy who engaged in a modified Delphi process to generate consensus on 1) the definition of survivorship, 2) aim and target users of the guideline, and 3) the potential important clinical issues in Japan. We conducted a web-based survey and held a panel meeting to obtain panelists’ feedback on the first draft proposed by secretariat. We then held a vote online and voted again until all items reached approval of 80% or more. After each round, iterative refinements were made based on panelists’ feedback. Results: Twenty-two experts were enrolled in the panel and participated in the four rounds of online voting and two face-to-face meetings. Ultimately, the panel reached consensus on the definition of survivorship, and the aim and target users of the guideline. Moreover, 11 of 17 key clinical issues were retained after the fourth vote: 1) Routine surveillance for secondary cancer, recurrent cancer, and metastasis; 2) Cooperation and coordination between primary care providers and specialists in cancer; 3) Staying physically active; 4) Being conscious of food and nutrition; 5) Maintaining a non-smoking lifestyle; 6) Vaccinations; 7) Assessment, care, and management of the effects of anticancer drugs on the cardiovascular system (e.g., cardiotoxicity); 8) Assessment, care, and management of psychological pain; 9) Assessment, care, and management of sleep disorders; 10) Assessment, care, and management of pain and numbness; and 11) Assessment of and support for employment-related issues. Conclusion: The panel’s consensus on the definition of survivorship, aim and target users of the guideline, and 11 important clinical issues must be a compass for the development of comprehensive cancer survivorship guidelines in Japan. The development of guidelines based on this consensus will have a positive impact on both clinical outcome among cancer survivors and cancer survivorship research in Japan.