Background: Polycystic ovary syndrome (PCOS) is one of the most prevalent endocrine disorders in females of reproductive age, with a prevalence of 20%-33% in the general population. Interleukin (IL)-34 is a recently explored proinflammatory cytokine and is an important modulator in different disease types. However, the function of IL-34 in PCOS has yet to be investigated. Objective: The purpose of this study was to determine the IL-34 serum level in women with PCOS and to compare it to that of a relatively healthy control group. Focusing on its relationship with IL-6, TNF-α, and IL-1β and homeostatic model assessment for insulin resistance (HOMA-IR), triglyceride, and low-density lipoprotein cholesterol (LDL-C). Materials and Methods: In this study, blood samples were obtained from 100 women with PCOS and 100 healthy control women for the purpose of estimating their serum levels of IL-34, IL-6, TNF-α, and IL-1β using the enzyme-linked immunosorbent assay technique. Results: Serum levels of IL-34, IL-6, TNF-α, and IL-1β were all higher in PCOS women than in healthy controls, and the difference was highly statistically significant. Serum IL-34 concentration was positively correlated with IL-6, TNF-α, and IL-1β concentration. Additionally, serum concentrations of IL-34 were positively correlated with HOMA-IR, triglyceride, and LDL-C. Conclusion: When compared to normal women, IL-34, IL-6, TNF-α, and IL-1β levels were highly statistically significant in PCOS, and these high levels were associated with other cytokines (IL-6, TNF-α, and IL-1β), HOMA-IR, triglyceride, and LDL-C.