The integrity of p53 machinery is crucial for platinum activity, while p53 mutation is frequent in high-grade serous ovarian cancer (HGS-OC). This study aimed to evaluate the link between p53 mutations, platinum sensitivity (PS), and the platinum-free interval (PFI) in patients with HGS-OC. We prospectively analyzed 159 consecutive women with ovarian cancer who underwent surgery. The somatic mutational status of BRCA, HRD, and TP53 (according to structural, hotspot, and functional classification) was evaluated. Among enrolled patients, 82.4% of cases were TP53-mutated (MT), and 27.8% were BRCA-MT. The distribution of TP53 mutation categories did not differ significantly between the BRCA-MT and wild-type (WT) cases. In the entire population, the proportion of PS patients was significantly lower in TP53-MT compared to TP53-WT (