Background: Somatic p53 mutations (TP53m) have been reported in most high grade serous ovarian cancers (HGSOC). We aim to investigate the impact of the type of functional TP53m on prognosis and determine if p53 immunohistochemistry (IHC) can be used as a surrogate for mutations. Methods: HGSOC patients (pts) enrolled in an institutional molecular screening program (NCT01505400) were evaluated. Functional mutations of TP53 were classified as gain of function (GOF), loss of function (LOF), loss of function dominant-negative (LOF-DN) and variants of unknown significance (VUS), as adapted from IARC TP53 database. A Cox proportional hazard model was used to see if the type of TP53m impacted overall survival (OS) and linear regression analysis for the correlation between first platinum free interval (PFI) and TP53m. IHC was performed for p53 using the D07 antibody. The functional type of TP53m was correlated with IHC (as reported in patient chart) germline BRCA1/2 (gBRCAm) mutation and the use of neoadjuvant chemotherapy using Fisher’s exact test. Illumina MiSeq next-generation sequencing (NGS) was used to detect TP53m. However, certain TP53 missense mutations or large deletions may not be detected with this technology. Results: 240 pts were available for analysis of TP53 by NGS. 183 (76%) were found to have a TP53m. Of these, the pts characteristics were: median age of 57 years, 170 pts (93%) with stage III/IV, 41 pts (22%) gBRCAm, median number of lines of chemotherapy 3 (1-8), and 93 pts (50%) had neoadjuvant chemotherapy. The distribution of TP53m by functional classification was 50 GOF (27%), 51 LOF (28%), 28 LOF-DN (15%) and 53 VUS (29%). OS was available for 132 (72%) pts and PFI for all. The type of functional mutation was not related to OS (p = 0.24) or PFI (p = 0.70). 90 (49%) pts had IHC done for TP53m. Overexpression on IHC (n = 69) was significantly correlated with GOF, LOF and LOF-DN and VUS were significantly correlated with null phenotype (n = 21) (p < 0.001). There was no correlation between TP53m function and gBRCAstatus (p = 0.93) or with prior chemotherapy use (0.62). Conclusions: The functionality of TP53m is not correlated to outcome in our cohort. Pts with null phenotype on IHC tend to have TP53m VUS which needs further characterization. .