Background: Aim was to study prevalence of thyroid dysfunction in type II diabetes mellitus (T2DM) patients.Methods: The present study was a cross sectional observational study, which focused on cases of diabetes mellitus. Study was conducted in Departments of Medicine, SBKS MI & RC, a tertiary care centre for a period of 6 months. All the patients of T2DM were included. Total of 263 patients were enrolled which involved indoor, outpatient and diabetic clinic attending patients. A detailed history taking, clinical examination and relevant investigations (Hb%, Total count, platelet count, serum creatinine, FBS, PP2BS, HbA1C, S.TSH, F.T3 and F.T4). Appropriate statistical analytics were used and important correlations and conclusions were drawn.Results: A study of thyroid dysfunction (TD) in T2DM patients which included 263 diabetic patients, out of them 67 had thyroid dysfunction. Out of these 67 patients 43 were female and 24 were male. This suggests that female was more prone to thyroid dysfunction than males. Out of 67 TD patients, 42 were above the age of 50 year. So, as the age increases the prevalence of TD also increases thyroid dysfunction also depends on the glycaemic control of the patients. Out of 67 patients 22 patients had>8.0 HbA1C level. In our study we found that as the glycaemic control became poorer the prevalence of TD increase in hypothyroid but not in hyperthyroidism.Conclusions: Following conclusions were drawn from this study TD is more common in female than male, more after the age of 50 year, in T2DM patients. Hypothyroidism is more common with poor glycaemic control and long duration of T2DM patients. But for hyperthyroidism data which we evaluated was not significant and further conclusion bigger study is needed.