Background <p>Adenomyosis is a gynecological condition that frequently coexists with gynecological malignancies and has been shown to influence disease outcomes. However, its impact on ovarian cancer prognosis remains unclear. This study aimed to investigate the relationship between adenomyosis and clinicopathological and prognostic features in ovarian cancer patients.</p> Methods <p>We retrospectively analyzed 226 patients with ovarian cancer who underwent surgery between 2020 and 2023. The patients were divided into two groups based on the presence (n = 114) or absence (n = 112) of adenomyosis, confirmed by histopathological examination. Clinicopathological characteristics, including histological subtypes, disease-free survival (DFS), and overall survival (OS) were compared between the groups with a median follow-up of 36&#xa0;months.</p> Results <p>Patients with adenomyosis demonstrated more favorable characteristics, including early stage disease (54.3% vs 39.2%, p = 0.048), lower-grade tumors (55.2% vs 31.2%, p = 0.049), and smaller tumor sizes (39.4% vs 26.7%, p = 0.043). Adenomyosis was significantly associated with endometrioid subtype (OR = 2.89, p = 0.043) and negatively associated with serous carcinoma (OR = 0.39, p = 0.034). Three-year DFS was significantly better in the adenomyosis group (79.2% vs 73.9%, p = 0.01), particularly in high-grade tumors (80% vs 58%, p &lt; 0.05). No significant difference was observed in overall OS (73.3% vs 73.1%, p = 0.14), although high-grade tumors with adenomyosis showed improved OS (71% vs 57%, p &lt; 0.05).</p> Conclusion <p>The presence of adenomyosis in patients with ovarian cancer was associated with favorable clinicopathological features, particularly endometrioid histology and low-grade tumors, and improved survival in high-grade tumors. These findings suggest a potential biological interaction between adenomyosis and ovarian cancer that warrants further investigation for personalized treatment approaches.</p>