Elevated levels of DNA damage, decreased efficacy of DNA repair and high susceptibility to mutagens have been associated with type 2 diabetes mellitus. Micronuclei (MN) are a sensitive indicator of genetic damage and a marker of DNA damage. MN is also a morphological marker of chromosomal instability. So the presence of MN in cells reflects structural chromosomal aberrations arising during mitosis. Our aim was to evaluate the frequencies of micronuclei, as a biomarker for DNA damage, in Giemsa stained buccal cells of T2DM patients and healthy controls. A case-control study of seventy six patients with T2DM and twenty five control group participants were recruited from different areas of West Bengal for determination of frequency of MN. All procedures were done with the informed consent of participants. In the present study, frequency of MN found in T2DM patients was 4.08±3.77, which was much higher than the control group participants (1.1±0.9). Frequency of MN increased due to the elevated level of DNA damage in these patients than the controls. Hence, in the present study, increased DNA damage may be due to increased oxidative stress leading to genomic instability, which in turn may lead to the progression of T2DM and its complications and contribute to an increased risk for cancer. This depicts that MN may be a useful constituent in a panel of biomarkers for the risk of late diabetic complications and can be a predisposing factor for development of cancer. INTRODUCTIONType 2 diabetes mellitus (T2DM), the most frequent subtype of diabetes, comprises a complex heterogeneous group of metabolic diseases characterized by high levels of blood glucose (hyperglycaemia) and impaired insulin action and/or insulin secretion.The number of people with T2DM is increasing in every country with 80% of population with DM living in low-and middle-income countries [1]. It is estimated that T2DM affects about 150 million people worldwide and it is expected to rise to about 439 million people by the year 2030 [2,3].India ranked first in the world for the prevalence of the disease, followed by China and USA [4].There are currently approximately 40.9 million patients suffering from diabetes mellitus in India and it is expected to rise to about 69.9 million by the year 2025 [5]. Anticipating an epidemic like increase in the number of diabetic patients, India is being referred to as the 'diabetic capital of the world [6]. About 31.0% populations of West Bengal are suffering from T2DM [7]. The incidence of T2DM varies substantially from one geographical region to the other as a result of environmental and lifestyle risk factors [2]. One of the factors associated with diabetic complications is the process of non-enzymatic glycation of proteins, lipids and nucleic acids, with subsequent formation of advanced glycation end products (AGEs) [8]. One of the main consequences of this adverse action is the formation of oxidative stress (OS). Formation of glycation end products leads to OS and subsequent DNA damage via the oxidation of DNA base...