Statement of the Problem: selection of prosthetic materials is a critical factor affecting the long-term success of implant supported restorations. PEEK poly-ether-ether ketone-is a quite new polymer used for dental applications. However, there are limited data available concerning Stress analysis and strain development of PEEK restorations as implant superstructure. Introduction; Materials and Methods; A total of 14 frameworks (n=7) were fabricated of Zirconia and PEEK by milling technique, divided into two equal groups to be randomly seated on its corresponding titanium abutment and then subjected to 5000 thermo-cycles. Strain gauge method was selected in this study to assess strain development where strain gauges were adhesively bonded mesial and distal to each implant-abutment unit and data were recorded using a strain meter device. Results; As regards the overall strain (mean of the four channels): there was no statistically significant difference between the two groups Conclusion; PEEK frameworks revealed slightly higher strain compared to zirconia with no significant difference in the over-all strain channels.