Metabolic syndrome (MetS) leads to changes in enzymatic activities, oxidative and inflammatory parameters. Adenosine deaminase (ADA), dipeptidyl peptidase IV (DPP-IV), butyrylcholinesterase (BuChE) and γ-glutamyltransferase (γ-GT) activities, C-reactive protein (hsCRP) and nitric oxide levels (NOx), as well as oxidative stress markers were analyzed in 39 subjects with MetS and 48 controls. Also, the influence of body mass index (BMI) and anthropometric measurements were evaluated. Disturbances in antioxidant defenses and higher γ-GT and BuChE activities, NOx and hsCRP levels were observed in subjects with MetS. These findings remained associated with MetS after adjustment for BMI, except for hsCRP. ADA was correlated with age, insulin levels and HOMA-IR index in MetS. DPP-IV and total cholesterol (TC), BuChE activity and TC, and VIT C and hsCRP levels also were correlated. The analyzed parameters may reflect the inflammatory state of the MetS, and could contribute to prevention and control of various aspects of this syndrome.