To evaluate peri-implant stresses generated using finite element analysis for cobalt chromium and zirconium frameworks for a maxillary all on four prostheses. Material and methods: Three-dimensional finite element models of an edentulous maxilla restored with a prosthesis supported by 4 implants were reconstructed to carry out this analysis. The anterior implants were placed vertically and bilaterally in the lateral-canine area, whereas the posterior implants were placed with a 17-degree distal angulation at the second premolar area. Multi-unit abutments were used for all implants. A framework of the first model made of zirconia was designed, while for the second model a cobalt-chromium framework was planned. Results: The Von Mises stress of the posterior implant and multi-unit abutment was greater than anterior implants when using both frameworks. The von miss stresses on the co-cr framework was 134.93MPa , compared to 131.88 Mpa for zirconia framework . Both framework showed very similar in von misses stresses. Conclusion: The use of either cobalt chromium or zirconium frameworks with an all on four prosthesis for the edentulous maxilla is considered to be a reliable treatment option.