Background: The renin-angiotensin system (RAS) is involved in regulation of angiogenesis, cell proliferation, desmoplasia and immunosuppression. Angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) may have antitumor effects partly by inhibiting transforming growth factor (TGF)-β, a major resistance mechanism in bladder cancer. Methods: Patients (pts) with muscle invasive bladder cancer (MIBC) treated or not treated with ACEi/ARB while receiving preceding radical cystectomy (RC) were assessed for pathologic complete response (pCR) defined as pT0N0 and overall survival (OS). Pathologic features, performance status, clinical stage, type and number of cycles of NAC, and presence of grade ≥3 toxicities were collected retrospectively. The Kaplan-Meier method was used to estimate overall survival (OS). Logistic and Cox regression was used to explore factors potentially prognostic for pCR and OS respectively. Results: 187 patients received NAC followed by RC. The mean age at the time of NAC was 65. 71% were male and 29% were female. Of the 187 patients, 61% received Cisplatin/Gemcitabine and 28.3% received dose dense MVAC. Of patients receiving NAC, 53 (28%) had a pCR. The 5-year OS was 64%. There were 41 (21.9%) patients taking an ACEi and 24 (12.8%) patients taking an ARB at the start of NAC. Of the 41 patients who took an ACEi, 17 (41.5%) had a pCR; of the 146 patients who did not take an ACEi, 36 (24.7%) had a pCR. ACEi intake during NAC was the only factor associated with pCR on multivariable analysis (odds ratio of 2.17 [95% CI 1.05-4.48] p = 0.037). pCR was the only factor shown to be associated with significantly improved OS (Hazard Ratio 0.18 [95% CI 0.07-0.45] p = < 0.001). After adjusting for pCR, ACEi was not significantly prognostic of OS (HR = 1.12, 95% CI = 0.60 to 2.09, p = 0.72). ARB intake while receiving NAC was not associated with pCR or OS. Conclusions: ACEi intake was associated with significantly increased pCR in patients with MIBC receiving NAC, and pCR was the only significant factor associated with OS. We hypothesize that ACEi may augment the activity of NAC and increase pCR, which translates to improved OS. ACEi intake was not associated with improvement in OS potentially due to competing causes of mortality in patients requiring ACEi. Our data requires validation.