This study was conducted on eighteen patient to compare between implant-supported telescopic retained mandibular overdentures reinforced by metal framework (Co-Cr) or injectable resin (PEEK) in terms of retention and patients satisfaction. At the beginning, conventional complete dentures were constructed for all the patients. A CBCT was performed before implant surgical procedure with the aid of radiographic stent. Three implants were placed in a conventional manner interforaminally. After suture removal the implants were left for three months to allow for osseointegration and throughout the healing period the patients were instructed to wear their conventional dentures. After the osseointegration period, the prosthetic phase was initiated where the 1ry copings for all the patients were fabricated from cobalt chromium. Then the patients were randomized to be divided into two groups identical in number, 9 patient in each group. The first group: received a metal framework with secondary copings. The second group: received an injectable PEEK framework with secondary copings. Retention was measured for each group (baseline, 1month, 3months, 6 months and 9 months) by using a digital force gauge where pulling force was applied gradually until the denture was dislodged. The retentive force was measured for the initial separation of the telescopic crown.Patients‘ satisfaction was assessed using VAS of 100mm in length by asking the patient to rate his perception. Patient satisfaction included five domains; general satisfaction, stability, chewing efficiency, esthetics and speech. The assessment was made at baseline (after 1 week of denture insertion), one month, three months, six months and nine months follow- up period. Group II showed higher values of retention and Mean Patient Satisfaction Score (MPSS) compared to Group I.