Purpose: To evaluate the clinical outcome of maxillary prostheses supported by four immediately loaded zygomatic implants in the rehabilitation of edentulous patients with severe atrophic maxillae after 5 years of function. Materials and methods: Out of a total of 17 consecutive patients with severe atrophy in the maxillae (Cawood and Howell classification C-VI and D-V or D-VI) and whom were rehabilitated using four immediately loaded zygomatic implants, three were lost during follow-up. Outcome measures were success rates of the prostheses, success rates of the zygomatic implants, complications and oral health-related quality of life (OHIP-14 questionnaire). Results: In 14 patients assessed at 5 years after operation, no prosthesis or zygomatic implants failed, although one implant placed in an unfavourable position was not used. Fifty percent of the patients had complications, which included penetration of the orbital cavity during the drilling procedure (1 patient), infection followed by a fistula at one zygomatic implant (1 patient), sinusitis (2 patients), fracture of the abutment screw (1 patient) and fracture of the prostheses (2 patients). All complications were resolved without clinical consequences. At 5 years the mean score of the OHIP-14 was 3.8, which is similar to that of the general population. Conclusion: Results at 5 years indicate that the use of four immediately loaded zygomatic implants is a reliable approach for successful rehabilitation of edentulous patients with severely atrophied maxillae. Keywords: alveolar bone loss/rehabilitation, dental implantation/endosseous methods, dental prosthesis, immediate dental implant loading, implant-supported, zygoma/surgery