Introduction: Diabetes Mellitus (DM) is the most common metabolic disorder in nearly 5-10% of western population aged more than 40 years. Blood glucose estimation is the main stay of diagnosis and management of DM. Aim: Compare the blood glucose estimation methods from capillary blood and venous blood by glucometer and also with venous plasma glucose estimation by auto analyzer and to find out variation percentages in results. Material & Methods: 196 patients attending Outpatient department of a tertiary care level hospital who were advised blood glucose estimation were selected. Finger prick (capillary) blood glucose & venous blood glucose estimation was done by glucometer; and plasma glucose estimation was done by auto analyzer in laboratory. Result: Average blood glucose value in all 196 subjects shown as (C), (V) & (P), 169.54 mg/dl, 184.11 mg/dl &155.93 mg/dl respectively, suggests highest value in venous sample (V) and lowest in Plasma sample (P). The difference between venous sample & capillary sample is =14.574 mg/dl, Venous sample & plasma sample is = 28.185 mg/dl and capillary sample & plasma sample is = 13.610 mg/dl. Range of differences between different methods is between 13.610 to 28.185 mg/dl. Highest values are in and lowest in 28.185 mg/dl &13.610 mg/dl, respectively. The percentage variation value (X), (Y) & (Z) are 91.33%, 19.90%, &90.31% of subjects, respectively, are showing less than 15% variation difference in blood glucose value.Conclusion: Capillary blood glucose estimation by glucometer is a better alternative to venous plasma glucose estimation for diagnosis; follow up and in emergency conditions in diabetic as well as non-diabetic patients. Venous blood glucose estimation by glucometer is not advisable as a routine method, but it is advisable when patient refuses for a second pin prick of finger.