Purpose was to evaluate the retention of thermo-elastic acrylic resin versus conventional heat cured acrylic resin. Material and Methods: Ten completely edentulous patients were divided into two groups, patients in this first group received one maxillary and mandibular complete denture made of conventional heat cured acrylic resin, and wearing it for one month, and then the mandibular denture was replaced by another one whose denture base was made of thermoelastic acrylic resin. Patients were instructed to wear the dentures for one month before evaluation of retention. While in the second group, the other patients received one maxillary conventional heat cured acrylic complete denture and one mandibular thermo-elastic denture, and wearing it for one month, and then the mandibular denture was replaced by another one whose denture base was made of conventional acrylic resin. Patients were instructed to wear the dentures for one month before evaluation of retention. Results: The results of this study showed thermo-elastic mandibular denture base had recorded statistically significant higher retention mean value than conventional cured mandibular denture base p ≤ 0.001. Conclusion: Thermo-elastic heat cured acrylic resin (versacryl) denture exhibit more retention than that of the conventional heat cured acrylic denture.