Purpose: To validate guided surgery for zygomatic implants (ZIs) by analyzing the final position of the implants relative to the preoperatively planned position. Material and Methods: Five patients with fully edentulous atrophic maxillae treated with four ZIs through a fully guided implant surgical approach were evaluated. The preoperative phase included digital planning, through which the surgical guide was designed and created. Analysis of the guided surgery accuracy was carried out by superimposing the digital planning over the final position of the implants using preoperative and postoperative CBCT. The radiologic evaluation included implant angular deviation, entrance deviation, exit deviation, platform deviation, and apex apicocoronal and mesiodistal deviation. Results: All five patients (two men and three women; mean age: 61.8 ± 3 years) were each treated with four ZIs using a fully guided approach with an extrasinusal path, obtaining ideal emergence of the implants. Superimposition comparison found a mean axial angular implant deviation of 0.79 ± 0.41 degrees and a mean implant entrance deviation of 0.95 ± 0.26 degrees. The platform deviation was 0.62 ± 0.19 mm buccopalatally and 0.76 ± 0.14 mm mesiodistally, while the apical deviation was 0.42 ± 0.13 mm buccopalatally and 1.06 ± 0.37 mm mesiodistally. Conclusions: Guided surgery in zygomatic implants appears to be sufficiently accurate to make it a safe and predictable technique.