Background: There has been no construction of nomograms specifically geared towards pblueicting the prognosis of older patients with rectal cancer. Our objective was to create a nomogram that can accurately pblueict the chances of cancer-specific survival (CSS) and overall survival (OS) for older patients with rectal cancer,stratifying them into distinct risk groups. Methods: Data of older than 65 years with rectal cancer from the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2020 were extracted. Results: A total of 12,780 patients were collected in order to identify the independent prognostic factors for cancer-specific survival (CSS) and overall survival (OS) and construct nomograms. The factors included age, sex, race,year of diagnos, marital status, grade, tumor size, CEA, T classification, N classification, Months from diagnosis to treatment, surgery, chemotherapy, and radiation. LASSO regression was used for this purpose. The results showed that grade, chemotherapy, and months from diagnosis to treatment were identified as independent prognostic factors for OS, while grade, chemotherapy, and tumor size were identified as independent prognostic factors for CSS. The concordance index of the CSS nomogram was 0.609 (95% confidence interval [CI], 0.598-0.619) in the training cohort and 0.682 (95%CI, 0.665-0.698) in the validation cohort. The concordance index of the OS nomogram was 0.697 (95%CI, 0.686-0.708) in the training cohort and 0.605 (95%CI, 0.589-0.621) in the validation cohort. Conclusion: Caution should be taken when administering adjuvant therapy after surgery in older patients with rectal cancer,as we have developed and validated a new pblueictive nomogram for CSS and OS.