Purpose: No information is available on the perception of the quality of care in patients treated for periodontitis. The purpose of this article was to assess how periodontitis-affected patients perceive the quality of periodontal treatment (PT) and to measure the factors which may influence it. Materials and Methods: 306 subjects who completed PT were invited to participate. Questionnaires and visual analogic scales (VAS) evaluating perception of quality of care, symptoms, and oral health related quality of life (OHRQoL) were handed out. Oral and periodontal indicators were collected before and after treatment. The impact of different factors on perception of quality was assessed with a regression model. Results: Quality evaluation was high yet unrelated for both patients and clinicians (p = 0.983). Quality was negatively influenced by the number of residual oral infections (p 0.001), patient's age (p = 0.07) and presence of residual pain at completion of PT (p = 0.02). Professionalism, kindness of the staff and communication skills were the characteristics mostly appreciated. The OHRQoL was influenced by the number of residual teeth (p 0.001), increasing age of patients (p = 0.08), number of residual infections (p 0.01) and pain (p = 0.04). Conclusions: Patients' quality perception appeared to be influenced by clinical and emotional aspects. Oral care providers should be aware of the impact of non-clinical factors in patients' appreciation of quality of treatment. Keywords: oral health related quality of life, periodontitis, quality of care