Objective: The aim of the study was to assess the clinical performance of implant-supported mandibular complete fixed prostheses with conometric retention after 3 years of functional loading. Materials and methods: In this retrospective study, patients treated with implant-supported mandibular complete fixed prostheses with conometric retention were considered. Standardized radiographic examinations were performed to assess the marginal bone. Radiographs were acquired at the time of prosthesis insertion and at the 3-year follow-up, and marginal bone loss was calculated. The occurrence of implant failures, and biological and technical complications was registered. Results: Thirty-nine patients were selected. At the 3-year follow-up, 134 out of the 160 placed implants did not show any marginal bone loss and 4 of them had been lost. The percentage of restorations free of technical complications was 71.8% during the entire follow-up period. Complications: that occurred in restorations were as follows: veneer fracture (n = 4), framework fracture (n = 3), loss of retention (n = 2) and need for relining (n = 2). Mucositis was recorded in 1 patient and it was successfully treated. Conclusion: The clinical performance of implant-supported mandibular complete fixed prostheses with conometric retention after 3 years of functional loading showed a low rate of marginal bone loss and technical complications. Owing to the easy retrievability, all complications were successfully treated.