Aim of the study: This clinical study was performed to evaluate outcome of double mini implants versus single standard implant replacing lower first molar restored with metal-ceramic crown. Patients and Methods:A total of 30 implantswere installed in 20 patients (14 females and 6 males);aged from 21 to 52 years. Patients were classified into the following two equal groups, (n=10) according to the implant diameter.GroupΙ: Double mini (one piece) dental implants were inserted into edentulous area of mandibular first molar using flapless technique.GroupΙΙ: One standard (two piece) dental implant was inserted using flap approach. Implants were restored with metal-ceramic crowns.After 4 months healing period with provisional crowns implants were examined at baseline,6,12,and18 months after definitive cementation of crowns.Standardized periapical radiographs were done.Radiographic bone loss were calculated as well as clinical parameters including probing depth, plaque index, gingival index andimplant mobility.Also,Prosthetic evaluation between two groups have been performed throughout the entire follow-up. Results:There was no statistically significant difference between two groupsthroughout the entire follow-up regarding probing depth at baseline (p1=0.1), at 6 months (p2=0.3),at 12 months (p3=0.4) and 18 months(p4=0.2),plaque index (p1=0.08, p2=1.0,p3=0.6, p4=0.6), gingival index(p1=0.07, p2=0.18, p3=0.6, p4=0.3) and implant mobility(p1=1.0, p2=0.3,p3=0.3, p4=0.3).On the other hand,there was statistically significant difference (p=0.002) between both groups regarding marginal bone loss at 18 months.However, there was no statistically significant difference between two groupsregarding marginal adaptation,anatomic form andsurface texture(p=0.7) throughout the entire follow up.Also,there was no statistically significant difference between two groups regarding color match(p1=0.2, p2=0.7,p3=0.7,p4=0.7) between both groups throughout the entire follow up. Conclusion: Within the limitation of this clinical study,it can be concluded that the double mini implant can be successfully used for replacing lower molars compared to the single standard implant.