BACKGROUND Preeclampsia is one of the leading causes of morbidity and mortality in pregnant women, if not attended. Numerous methods have been used to predict the onset of preeclampsia with different degrees of accuracy. These methods used included foetal, placental and maternal markers in different stages of pregnancy. Our study attempts to find out if there is an association between preeclampsia and Insulin resistance, and whether insulin resistance can be used as a biomarker for diagnosis of preeclampsia. METHODS This study was performed among one hundred pregnant women of age ranging between 18-35 years and having gestational age between 28 to 34 weeks. Around 200 of them were screened for preeclampsia. Fifty obstetric patients identified as having preeclampsia were included in the study as cases. Fifty healthy pregnant subjects having uncomplicated pregnancies and who have been normotensive throughout gestation were taken as controls (total 100). Whole blood samples and 24 hour urine samples were collected. Serum was used for estimation of glucose and plasma for insulin concentrations. 24 hour urinary protein was measured. Insulin resistance was calculated by HOMA-IR method. RESULTS The mean value of fasting blood glucose in preeclamptic women is 87.27 +/- 7.36 mg/dl and that in control is 75.3 +/- 12.02 mg/dl and is statistically significant (p=0.0548). The mean value of plasma insulin in preeclamptic women is 57.27 +/- 7.1 mu IU/ml and that in control is 26.43 +/- 4.23 mu IU/ml and is statistically very significant (p=0.0005). The mean value of insulin resistance in preeclamptic women is 12.46 +/- 2.61 and that in control is 5.69 +/- 2.14 and is statistically very significant (p=0.0005). CONCLUSIONS Insulin resistance can be used as a biomarker in diagnosis of preeclampsia.