Background: Assessment of malnutrition is important in cancer patients, especially in gastrointestinal cancer in Indonesia. The Scored Patient-Generated Subjective Global Assessment (PG-SGA), an instrument that allows interdisciplinary assessment of malnutrition and its risk factors, has yet to be available in the Indonesian version. Object: To produce a valid and reliable PG-SGA questionnaire in Indonesian while maintaining the English version's form, purpose, and meaning. Methods: The PG-SGA questionnaire was translated, culturally and linguistically adapted, following the International Society for Pharmacoeconomics (ISPOR) principles. Each question item in the questionnaire will be assessed based on content validity, comprehensibility, and difficulty, operationalized by calculating item and scale indices. A scaled score of 0.80–0.90 is considered acceptable, while a score of more than 0.90 is considered excellent. Results: The content validity of the entire PG-SGA questionnaire obtained an S-CVI of 0.92. The content validity score of the PG-SGA questionnaire on professional participants was S-CVI 0.91. The comprehensibility score of professional and general public participants was S–CI 0.89. The score for the difficulty of question items on the PG-SGA questionnaire with professional and general public participants obtained the results of S-DI 0.86 and 0.88. Conclusion: The translation and cultural adaptation of the PG-SGA questionnaire according to the ISPOR principles of successfully maintaining the format, purpose, and meaning of the Indonesian version of the PG-SGA questionnaire. The PG-SGA questionnaire's Indonesian version is now comprehensible and relevant for patients, the general public, and professionals. However, there are components of the professional questions that are considered difficult, so additional descriptions or brief explanations and training are needed, especially for physical examinations. © 2025 The Author(s)