Phthalates have been reported to increase the risk of various hormone-dependent cancers. However, there is still a lack of evidence regarding the association between phthalates and overall survival (OS) in advanced high-grade serous ovarian cancer (HGSOC). This study investigated the relationship between urinary phthalate metabolites and OS in patients with HGSOC using a nested case-control study within the Ovarian Cancer Follow-Up Study. We matched 159 deceased patients with HGSOC to 159 survivors by age at diagnosis, body mass index, and sampling date. Spot urine samples were analyzed for ten phthalate metabolites and five classes of phthalate molar sums via mass spectrometry. Conditional logistic regression models were employed to calculate odds ratios (ORs) and 95% confidence intervals (CIs), comparing the highest tertile with the lowest. We found that the highest tertiles of mono-2-ethyl-5-oxohexyl phthalates and monoethyl phthalates were associated with poorer OS, with ORs (95%CIs) being 4.24 (1.46, 12.32) and 3.28 (1.16, 9.22), respectively. Additionally, the highest tertiles of the sum of di(2-ethylhexyl) phthalate metabolites, the sum of high-molar-weight phthalate metabolites, and the sum of 10 phthalate metabolites, were associated with worse OS, with ORs (95%CIs) were 18.4 (4.14, 81.87), 9.28 (2.87, 30.08), and 5.94 (2.00, 17.64), respectively. Our study suggests that exposure to high levels of phthalates may be associated with poorer OS in patients with advanced HGSOC, particularly exposure to di(2-ethylhexyl) phthalate. Since it is widely used in personal care products, avoiding the use of these products may improve the OS of patients with HGSOC.