Abstract: Aim\ To observe whether obesity aggravate insulin resistance in essential hypertensive patients.\ Methods\ Oral glucose tolerance test（OGTT） was used to investigate the presence of insulin resistance.\ Serum glucose was measured by hexokinase assay and serum insulin and Cpeptide were measured by radioimmunoassay.\ Results\ Serum glucose, insulin and Cpeptide levels and areas under curve in obese and nonobese hypertensive persons were higher than those in normal persons after glucose load.\ Moreover, obese hypertensive patients had higher parameters than nonobese hypertensive patients.\ Compared with control group, molar ratios of Cpeptide/insulin in hypertensive subjects decreased at 2 and 3 hours at OGTT;\ however there were not significant differences between obese and nonobese hypertensive patients.\ Conclusion\ Obesity aggravate insulin resistance in essential hypertensive patients.