The bowel preparation process prior to colonoscopy determines the quality of the bowel preparation, which in turn affects the quality of the colonoscopy. Colonoscopy is an essential procedure for postoperative follow-up monitoring of colorectal cancer (CRC) patients. Previous studies have shown that advanced age and a history of colorectal resection are both risk factors for inadequate bowel preparation. However, little attention has been paid to the bowel preparation experiences and needs of predominantly older adult postoperative CRC patients.To explore the experiences and needs of older adult postoperative CRC patients during bowel preparation for follow-up colonoscopy.Fifteen older adult postoperative CRC patients who underwent follow-up colonoscopy at a tertiary hospital in Shanghai were selected using purposive sampling from August 2023 to November 2023. The phenomenological method in qualitative research was employed to construct an interview outline and conduct semi-structured interviews with the patients. Colaizzi's seven-step analysis was utilized to organize, code, categorize, summarize, and verify the interview data.The results of this study were summarized into four themes and eight sub-themes: (1) Inadequate knowledge about bowel preparation; (2) Decreased physiological comfort during bowel preparation (gastrointestinal discomfort and sleep deprivation caused by bowel cleansing agents, and hunger caused by dietary restrictions; (3) Psychological changes during different stages of bowel preparation (pre-preparation: Fear and resistance due to previous experiences; during preparation: Irritation and helplessness caused by taking bowel cleansing agents, and post-preparation: Anxiety and worry while waiting for the colonoscopy); and (4) Needs related to bowel preparation (detailed instructions from healthcare professionals; more ideal bowel cleansing agents; and shortened waiting times for colonoscopy).Older adult postoperative CRC patients' knowledge of bowel preparation is not adequate, and they may encounter numerous difficulties and challenges during the process. Healthcare professionals should place great emphasis on providing instruction for their bowel preparation.©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.