Inflammation caused by periodontitis may have numerous systemic effects. One of the mediators influenced by periodontitis is C-reactive protein (CRP). Aim of this study was to determine if healthy subjects without peridontitis have a lower CRP-concentration compared to patients with chronic periodontitis. Further it should be evaluated if CRP-level decreases after a nonsurgical periodontal therapy. 21 systemically healthy patients with periodontitis (PERIO) and 11 persons without periodontitis as control group (C) were included. All persons had a clinical examination and provided blood to determine the CRP level. Following initial assessment, the periodontitis group received nonsurgical periodontal treatment. 6 weeks later, a second examination and CRP analysis was done. At baseline, subjects with periodontitis had a higher CRP level than the control group (PERIO: 0,36 ±0,3 mg/dl; C: 0,29 ±0,3 mg/dl). Treatment reduced probing depths and bleeding score significantly. After treatment, CRP-level decreased (0,27 ±0,3 mg/dl), but the differences found were not statistically significant. The results of this study point out that patients with chronic periodontitis may have higher CRP-level compared to healthy subjects and that a nonsurgical periodontal treatment can decrease CRP-concentration. Schlagwörter: C-reaktives Protein, chronische Parodontitis, Entzündung, nichtchirurgische Parodontitis-Therapie