Accumulation of reactive oxygen species (ROS) can disrupt the antioxidant defense system, leading to oxidative stress that leads to pathological damage to vital human organs, including hormone-producing glands. Normal physiological function is subsequently disrupted and disorders such as Type 2 Diabetes Mellitus (T2DM) may develop. The critical role of the antioxidant defense system in counteracting ROS and mitigating oxidative stress is fundamental to understanding the pathogenesis of T2DM. In our study, we monitored the oxidant/antioxidant status in a selected Jordanian population to further elucidate this relationship. Our results show higher serum levels of Malondialdehyde (MDA); 0.230 ± 0.05 and 0.207 ± 0.06 μmol/l for the diabetic and the obese groups, respectively, relative to 0.135 ± 0.04 μmol/l for the non-obese healthy group. Lower activity of Catalase (CAT) was recorded among the diabetic (9.2 ± 3.2) and obese groups (11.0 ± 2.8), compared to the non-obese healthy group (12.1 ± 3.5). Significant elevations (P < 0.05) were observed in uric acid concentrations in diabetic and obese subjects: 451 ± 57 mg/dl and 430 ± 51, respectively, versus 342 ± 57 mg/dl in the non-obese healthy group. Moreover, no significant differences were obtained between all the studied groups for the serum albumin and total protein concentrations. Our findings demonstrate the potential role of oxidative stress in the development and occurrence of T2DM.