The aim of this cohort study was to determine whether periodontitis and gingivitis are associated with impaired salivary antioxidant status and increased oxidative injury. One hundred and twenty-nine patients attending a routine dental check-up were recruited for the study. Periodontal disease status was characterized using the Community Periodontal Index of Treatment Needs (CPITN) system. Total salivary antioxidant capacity and salivary ascorbate, urate and albumin were determined in a sample of whole unstimulated saliva. Protein carbonyl concentrations were determined as an index of oxidative injury. Patients in the lowest tertile of CPITN score exhibited decreased salivary delivery of antioxidants and specifically urate than patients in the upper tertile. Poor periodontal health was associated with increased concentrations of protein carbonyls in saliva. Women had significantly lower total antioxidant status than men, regardless of periodontal health. Periodontal disease is associated with reduced salivary antioxidant status and increased oxidative damage within the oral cavity.