The chemotherapy response score (CRS) is used to score histopathologic response to neoadjuvant chemotherapy (NACT) of patients with extrauterine high-grade serous carcinoma. This study was undertaken to determine if the CRS in the omentum, adnexa or when combined correlates with (1) progression-free survival (PFS) or overall survival (OS), (2) laparoscopic score of abdominal disease, (3) Cancer antigen 125 levels, (4) BRCA status, and (5) platinum-resistant disease. A total of 158 cases were retrospectively collected that received NACT between April 2013 and February 2018 at a single institution. The 3-tier Böhm CRS system was applied to the omentum and adnexa. Survival outcomes between scored subgroups were analyzed using Cox proportional hazards regression. Spearman rank correlation analyses were used to assess CRS and clinical data. A total of 119 cases were treated only with carboplatin/paclitaxel. Omental CRS was: 1 (23 cases, 19.3%), 2 (65 cases, 54.6%), and 3 (31 cases, 26.1%), whereas adnexal CRS was: 1 (50 cases, 42%), 2 (48 cases, 40.3%) and 3 (21 cases, 17.6%). The omental CRS was significantly associated with PFS as a 2-tier score (hazard ratio [HR]=0.612, 95% confidence interval [CI]: 0.378-0.989, P=0.045) but not associated with the PFS using the 3-tier score or with OS using either system. Adnexal CRS was not associated with OS but was significantly associated with PFS using the 3-tier (HR=0.49, 95% CI: 0.263-0.914, P=0.025) and 2-tier scores (HR=0.535, 95% CI: 0.297-0.963, P=0.037). The combined score was not associated with OS but was significantly associated with PFS using the 3-tier (HR=0.348, 95% CI: 0.137-0.88, P=0.026) and 2-tier scores (HR=0.364, 95% CI: 0.148-0.896, P=0.028). No CRS system used associated with laparoscopic assessment of disease. CRS in the omentum had no significant association with platinum resistance; however, the adnexal CRS 1/2 were 3 times as likely to develop platinum resistance compared with CRS 3 (relative risk=3.94, 95% CI: 1.03-15.09, P=0.046). The CRS, when used on the omentum, adnexa, and as a combined score, was significantly associated with PFS but not with OS. Adnexal CRS 1/2 are more likely to develop platinum-resistant disease. Therefore, the use of this pathology parameter may be useful for clinical management.