Purpose: To evaluate the clinical outcome of maxillary prostheses supported by four immediately loaded zygomatic implants after 1 year of function. Materials and methods: Seventeen patients were consecutively included and followed up to 1 year after prosthetic loading. Patients had severely atrophic maxillae (Cawood and Howell classification C-VI and D-V or D-VI) and were rehabilitated using four immediately loaded zygomatic implants, two in each zygoma bone. Outcome measures were success rates of the prostheses, of the zygomatic implants, complications and oral health-related quality of life (OHRQoL). Results: No patients dropped out. No zygomatic implants were lost, although one implant could not be used because it was placed in an unfavourable position. The orbital cavity was penetrated during the drilling procedure in one patient with no relevant clinical consequences. One patient experienced an infection followed by a fistula in one zygomatic implant, which was successfully treated. The average score from the OHIP-14 questionnaire was 3.4, which is similar to that of the general population. Conclusions: The present study suggests that four immediately loaded zygomatic implants can be used to rehabilitate patients with severely atrophied maxillae. Keywords: atrophic maxilla, immediate loading, zygomatic implants