To investigate whether GGT (gamma-glutamyltransferase) is associated to specific redox patterns. GGT, total and reduced aminothiols and malondialdehyde, were measured in 150 subjects (83 males, 48 (39-56) years), with none, one or more risk factors. By univariable analysis GGT was positively associated with age (p =0.001), male gender (p <0.001), risk factor number (p <0.001), ACE-inhibitors (p =0.008), anti-platelet agents (p =0.029), atherothrombotic events (p =0.001), glucose (p =0.013), malondialdehyde (p =0.029), plasma total cysteine (p =0.046) and inversely associated with plasma total glutathione (p =0.001). By multivariable analysis only male gender (p <0.001), risk factor number (p <0.001) and glutathione (p <0.001) were independently associated with GGT activity. These findings suggest that an ongoing redox imbalance, in terms of decreased plasma glutathione, is associated with raised GGT activity in subjects with a greater risk factor burden.