This study was conducted to compare the retention of maxillary CAD/CAM compete denture base obtained from either impression or cast scan versus conventionally processed heat cured acrylic resin one. Twelve patients fulfilling the eligibility criteria were recruited from the outpatient clinic of the Prosthodontics Department, Faculty of Oral and Dental Medicine, Cairo University. Each one the participant received three denture bases; CAD/CAM denture base from the impression scan (Imp Group) & CAD/CAM denture base from the cast scan (Ca Group) and a conventional heat cured denture base (C Group) as a control group. Retention was measured using the digital forcemeter. The highest mean retention value was found in {Imp Group} (23.63 ± 19.78) followed by {Ca Group} (20.09 ± 15.73), while the lowest mean retention value was found in {C Group} (17.69 ± 15.37). The results of the study showed no statistically significant difference among them at a P ≤ 0.05