Background: Fibromyalgia syndrome is characterized by chronic widespread pain accompanied by physical and psychological symptoms, often without a clearly defined pathological cause. Inflammatory markers derived from routine hematological parameters, such as the Neutrophil-to-Lymphocyte Ratio (NLR), Mean Platelet Volume (MPV) and Platelet Distribution Width (PDW), have been proposed as indicators of systemic inflammation. Objective: To evaluate NLR, MPV and PDW as inflammatory markers in patients with fibromyalgia. Patients and Methods: This case–control study was conducted at the Rheumatology Unit of Baghdad Teaching Hospital between July and November 2017. A total of 100 patients diagnosed with fibromyalgia according to the 2012 Canadian Guidelines and 50 healthy controls were included. Data collection involved structured questionnaires, clinical interviews and laboratory investigations. Hematological parameters, including MPV and PDW, were measured, while NLR was calculated manually from complete blood count data. Results: The neutrophil-to-lymphocyte ratio was significantly higher in patients with fibromyalgia (2.18) compared to healthy controls (1.92) (p = 0.033). Mean platelet volume was also significantly elevated in patients (8.3) relative to controls (8.0) (p = 0.045). In contrast, platelet distribution width was lower in patients (16.7) compared to controls (17.0), with a statistically significant difference (p = 0.01). No significant differences were observed in demographic variables between the groups. However, Receiver Operating Characteristic (ROC) analysis demonstrated that none of these parameters reached sufficient diagnostic accuracy (AUC<0.65) to serve as reliable diagnostic markers for fibromyalgia. Conclusion: Patients with fibromyalgia exhibit elevated NLR and MPV alongside reduced PDW, suggesting a possible inflammatory component in the disease. However, these hematological indices lack adequate diagnostic performance and should not be used independently for the diagnosis of fibromyalgia.