AIM: To determine the incidence of peri-implantitis in individuals with mucositis in a 5-year follow-up study. MATERIAL AND METHODS: A sample of 212 partially edentulous individuals, rehabilitated with dental implants, underwent periodontal and peri-implant clinical examinations in 2005 (baseline). Five years later, 80 individuals who had been diagnosed with mucositis in the baseline examination were re-examined. These individuals were divided into two groups: one group with preventive maintenance during the study period (GTP; n = 39), and another group without preventive maintenance (GNTP; n = 41). The following parameters were clinically evaluated: plaque index, bleeding on periodontal and peri-implant probing, periodontal and peri-implant probing depth, suppuration and peri-implant bone loss. The influence of biological and behavioural risk variables associated with the occurrence of peri-implantitis was analysed using univariate and multivariate logistic regression analyses. RESULTS: The incidence of peri-implantitis in the global sample was 31.2% (GNTP = 43.9% and GTP = 18.0%). CONCLUSION: The absence of preventive maintenance in individuals with pre-existing peri-implant mucositis was associated with a high incidence of peri-implantitis. Clinical parameters, such as bleeding on peri-implant probing, periodontal probing depth and the presence of periodontitis were associated with a higher risk of developing peri-implantitis.