Background: Polycystic Ovary Syndrome (PCOS) is one of the most prevalent endocrine disorders affecting women of reproductive age. Insulin resistance (IR) is a central metabolic feature of PCOS, often present even in non-obese individuals. Objective: This article explores the role of laboratory markers in the diagnosis and management of IR in PCOS through clinical cases and discusses their implications in clinical practice. Methods: A review of key biochemical markers associated with PCOS and IR was conducted, followed by the presentation of two clinical cases illustrating the utility of these parameters in diagnosis and treatment. Results: Elevated fasting insulin, HOMA-IR >2.5, and altered androgenic and gonadotropin profiles were observed. Treatment with metformin and ovulation-induction agents proved effective in managing IR and reproductive dysfunction. Conclusion: Laboratory testing is essential in the comprehensive evaluation of PCOS. Early identification of IR allows for timely interventions that can improve metabolic outcomes and fertility. Keywords: PCOS, insulin resistance, HOMA-IR, hyperandrogenism, infertility, laboratory medicine