Abstract: Present researchers studied the relation between insulin with free and total leptin in type 2 diabetic patients. Thirty non insulin dependent diabetic obese patients (age: 50 ± 12 year and BMI>30 kg m-2) and thirty non insulin dependent diabetic non obese patients (age: 49 ± 25 year and BMI<25 kg m-2) were studied. Free leptin was purified by Gel filtration Chromatography and the fractions were collected and then their free leptin was measured by a high sensitive ELISA Kit. Circulation total leptin and insulin were measured by ELISA. Circulation free and total leptin were significantly correlated to insulin (p<0.005). Free leptin concentrations were higher in women than in men (p<0.001). Ratio of free leptin to total in obese subjects is more than non-obese subjects (0.27 ± 0.1 vs. 0.03 ± 0.04, p<0.001). Ratio of free to total leptin showed a positive correlations with insulin (r = 0.58, p<0.001) insulin resistance (r = 31, p<0.015) and BMI (r = 0.86, p<0.001). The majority of leptin which circulates in obese individuals was free form. Presumably it is bioactive portion of hormone and thus obese subjects are resistant to free leptin. These observations are consistent with the view that free leptin levels in diabetes patients attributed to changes in serum insulin level and insulin resistant.