Background: The main goal of this study was to evaluate ischemia modified albumin (IMA), total antioxidant status (TAS), and total oxidant status (TOS) levels in treated essential hypertensive patients and to compare them with levels of normotensive subjects. Methods: In 45 hypertensive and 30 control subjects, serum levels of IMA were determined manually using a spectrophotometric Co(II)-albumin binding assay. TAS and TOS levels were evaluated spectrophotometrically. Lipid profile was estimated by routine methods. Results: Hypertensive patients had significantly higher levels of TOS and IMA (p = 0.020 and p = 0.034, respectively) and lower levels of TAS (p = 0.016) in comparison with control subjects. Serum levels of TAS were negatively correlated with TOS and IMA levels in the patient group. Serum levels of TOS were also positively correlated with IMA levels. There was no significant correlation between blood pressure and TAS, TOS, and IMA levels. Conclusions: Our results showed higher levels of IMA in hypertensive patients. We suggest that higher levels of IMA may result from increased oxidative stress and decreased antioxidant status in hypertensive patients.