BACKGROUND/AIMS: This study aimed to assess the frequency of fibromyalgia syndrome (FMS) in patients with type 2 diabetes mellitus (DM). Additionally, we aimed to evaluate the association of pain severity with glycemic control of DM. MATERIALS AND METHODS: Patients with type 2 DM who were being followed up in an endocrinology clinic were included in this study. FMS was diagnosed according to the 2010 criteria set by the American College of Rheumatology. The patients’ pain during the morning and sleep was evaluated by the Visual Analog Scale (VAS). Fasting blood glucose and hemoglobin A1c (HbA1c) levels were measured to assess the glycemic control of DM. Their quality of life was assessed with the Health Assessment Questionnaire (HAQ). RESULTS: Ninety-four patients (62 female, 32 male; mean age of 56.5±10.1 years) with type 2 DM and 40 healthy controls (26 female, 14 male; mean age of 52.3±10.1 years) were enrolled in this study. FMS was diagnosed in 19.1% of the diabetic patients and 7.5% of the control group (p=0.120). No significant difference was observed between the HbA1c levels of the type 2 DM patients with or without FMS (p=0.814). There was a weak negative correlation between VAS day and night scores and HbA1c levels in the diabetic patients (r=-0.20, p<0.01; r=-0.27, p<0.01, respectively). HAQ scores were higher in the diabetic patients with FMS when compared with those patients without FMS (p<0.01). CONCLUSION: FMS frequency (using 2010 ACR criteria) was higher in those patients with type 2 DM compared to the healthy controls. Furthermore, good metabolic control of DM decreased daily pain among the diabetic patients and increase their quality of life.