Background: Diabetes mellitus is a common metabolic disorder characterized by absolute or relative deficiencies in insulin secretion and/or insulin action associated with chronic hyperglycemia and disturbances of carbohydrate, lipid and protein metabolism. Homocysteine (Hcy) is a risk factor strongly linked to cardiovascular complications in Type 2 Diabetes mellitus (T2DM). Hcy requires 5-methyltetrahydrofolate as methyl donor and vitamin B12 as a co-factor. So, Vitamin B12 deficiency will lead to hyperhomocysteinemia. Biochemical and clinical vitamin B12 deficiency has been demonstrated to be highly prevalent among patients with type 1 and type 2 diabetes mellitus. Aims: To assess the serum homocysteine and vitamin B12 levels in type 2 Diabetes mellitus patients. Methodology: The present case control study was conducted at Dhiraj hospital, Piparia, Vadodara, Gujarat, India in which 80 subjects were enrolled, out of which 40 were cases of type 2 diabetes mellitus patients and 40 were controls. The age group for the study was 35 to 70 years. Blood samples were drawn to measure RBS, HbA1c, serum homocysteine and vitamin B12. Interpretation of data was done using Medcalc software. Results: The mean levels of serum homocysteine was higher in T2DM patients than normal healthy individuals, difference between them was statistically highly significant (p<0.0001). The mean levels of vitamin B12 was lower in T2DM patients than normal healthy individuals, difference between them was statistically highly significant (p<0.0001). There is no correlation found between Homocysteine, vitamin B12 & HbA1c. Conclusion: A significant increase in serum Hcy level was observed in T2DM patients in our study. Raised serum Homocysteine is considered as an early marker of B12 deficiency. Hyperhomocysteinemia will lead to cardiovascular complications. Therefore, the hyperhomocysteinemia could serve as another important marker of poor diabetic control and developing complications.