Disease related to peri-implant mucosal inflammation (PIMI) has been reported as one of the major factors leading to failure of dental implants. Many authors have suggested options for treatment of these lesions, ranging from simple mechanical debridement and regenerative surgical techniques to removal of the implant. Prognostic classification systems have become an integral part of dental practice because they provide direct guidance in planning treatment. However, there is limited evidence to support the appropriate classification of PIMI and the corresponding treatments, and a more specific prognostic system is required. Because the number of patients with implants is increasing, clinicians must be aware of PIMI as an entity with specific management requirements. This report describes a simple prognostic system to help clinicians to foresee the outcomes of PIMI treatment.