This study aims to compare the effect of adding Silica -oxide nanoparticles on surface roughness of partial denture framework constructed digitally with Poly(ether-ether-ketone) PEEK versus constructed with (CAD/CAM).Methodology: 80 Mandibular partially edentulous casts were constructed, PEEK is being introduced in the construction of the partial dentures, Partial dentures were divided into two groups.Group I: conventional fabrication of RPD framework which was subdivided into two Group IA: acted as a control, no fillers added, and Group IB: Ten weight percentage (10 wt. %) of hydrophobic nano-SiO2 incorporated with the PEEK. Then, Group II: CAD/CAM milled frameworks (Digital constructed also, subdivided into two groups Group IIA acted as a control, no fillers added, and Group IIB: (10 wt. %) of hydrophobic nano-SiO2 incorporated with the PEEK. a digital profilometer was used to determine the surface roughness of the specimens. Surface hardness was conducted by The Rockwell hardness test machine used in this study. ANOVA and Tukey tests were used for the statistical analysis (p < 0.05). Results: Group II (digital fabricated RPD) showed Statistically significantly lower surface roughness than Group I: conventionally fabricated using PEEK material. On the Other hand, the groups which incorporated with silica nanoparticles were showed statistically significant higher in surface roughness than the controlled groups which constructed with pure PEEK materials without any additives in both major groups either constructed with conventional manner of RPD or constructed with (CAD/CAM) digital manner.