Pentraxin-3 (PTX-3) is a multibiological protein involved in cumulus cell expansion, fertilization, and implantation. This study was designed to analyze how circulating PTX-3 levels change in women with polycystic ovary syndrome (PCOS). A total of 50 Turkish participants, 35 of whom had PCOS and 15 of whom were fertile, were included in the study. Patients in the PCOS group were divided into 4 different phenotypes according to the NIH criteria (phenotypes A-D). The number of patients in phenotype A was the highest 13 (37.1%). In the calculations made without phenotyping, the serum ptx3 levels of the PCOS group were found to be significantly lower compared to the fertile control group (3.32 ± 0.73 ng/mL vs 4.97 ± 1.29 ng/mL; P < .001). The ptx3 value of phenotypes A and B was significantly lower than phenotype D (P = .008 and P = .009, respectively). When the phenotypes were compared with the fertile control group, the PTX-3 levels of phenotypes A and B were significantly lower than the fertile group. Although the ptx3 levels of phenotypes C and D were lower than the fertile group, the difference did not reach statistical significance. This is the first study to investigate serum ptx3 levels by phenotype in PCOS. While serum PTX-3 levels decreased in phenotypes A and B, ptx3 levels in phenotypes C and D were similar in fertile patients.