Introduction: This study was aimed to assess the prevalence of islet cell autoantibodies (ICAs) in type 2 diabetes mellitus (T2DM) patients and to compare some clinical and metabolic markers between ICA-negative and ICA- positive groups in South Khorasan province, East of Iran.Methods: In this cross-sectional study, 384 T2DM patients, all over 30 years old, were selected. None of the patients needed insulin therapy for at least 6 months following diagnosis. Demographic data including gender, age, age at diagnosis, disease duration, health status, family history of diabetes, body mass index (BMI) and treatment type were collected from all subjects. ICA assays were conducted using commercial enzyme-linked immunosorbent assay (ELISA) kits. In addition, blood pressure, as well as cholesterol, serum C-peptide and HbA1c levels were compared between ICA-negative and ICA-positive groups. Data were analyzed using SPSS software and P < 0.05 was considered as statistically significant.Results: ICA was detected in 1.30% of all diabetic patients. Compared with ICA-negative patients, ICA-positive subjects had significantly lower median age (P = 0.000), lower median disease duration (P = 0.001), lower C-peptide level (P = 0.006) and worse glycaemic control (HbA1c, P = 0.040). Furthermore, autoantibody-positive patients had more need for insulin therapy (P = 0.022). No significant correlation was found between ICA prevalence and family history of diabetes (P = 0.262), mean fasting blood glucose (FBG) (P = 0.282), BMI (P = 0.054), blood pressure (P = 0.070) as well as cholesterol levels (P = 0.888).Conclusion: Autoantibody screening is recommended in T2DM patients, especially non-obese patients under 40 years old, showing worse glycaemic control.