Background: RTOG0521 and STAMPEDE showed improved Overall survival (OS) and progression free survival (PFS) respectively, of ACT (adjuvant chemotherapy) to ADT (androgen deprivation therapy) and RT (adjuvant radiotherapy) in HrPC (High Risk localized Prostate Cancer). The median age of males in these trials is in 60’s. We present an observational study reporting OS on addition of ACT to ADT and RT in male age > 65 with HrPC. Methods: A retrospective national cancer center database (NCDB) (2004-2015) analysis was done. Patients aged >65 years with non-metastatic HrPC who underwent ADT and RT with or without ACT were included. Group1 included RT+ ADT+ ACT, Group2 included RT+ ADT. OS was estimated using Kaplan Meier analysis, reported for sub groups based on age. An adjusted hazard ratio (aHR) was calculated utilizing a Cox proportional hazard regression model. Results: 1,380,357 patients with HrPC were identified. 11734 met our inclusion criteria; 128 in Group1 and 11606 in Group2. Median Age, Gleason and PSA were: Group1- 72, 9, 14.6, Group2- 74, 9 and 14. Patients who received ACT were more likely to be younger and treated in an academic setting. OS stratified by age is depicted in table. Among patients ≥ 75, OS was uniformly worse with ACT with non-significant p value (p=0.08). The aHR, group 1 vs group 2 is 1.22, 95% CI = 0.96-1.57, p=0.11, when adjusted for Age, Facility Type, Insurance, and Charlson-Deyo Score (CDS). Conclusions: Very elderly patients ≥75 years were not likely to get ACT. OS was not improved by addition of chemotherapy, at age ≥ 65yrs and more prominent at age ≥ 75. Limitations of observational database study are lack of randomizations, missing information, physician bias on choices of ACT, RT and ADT.