Objective: To perform a retrospective study on immediately loaded implants supporting mandibular overdentures. Method and Materials: From the period between July 1996 and October 2004, 50 patients were selected in whom 200 implants had been inserted (4 implants per patient) in the interforaminal area, rigidly connected with a U-shaped bar, and then loaded with a mandibular overdenture. Implant diameter and length ranged from 3.4 to 5.5 mm and from 10.0 to 18.0 mm, respectively. Sixty implants were placed after extraction, and bone quality was D1 in 22 cases and D2 in 178 cases. Because no implants were lost (ie, survival rate, 100%) and no statistical differences were detected among the studied variables, no or reduced crestal bone resorption was considered as an indicator of success rate to evaluate the effect of several host-, surgery-, and implant-related factors. A general linear model was then performed to detect those variables statistically associated with crestal bone resorption. Results: No implants were lost (ie, survival rate, 100%) after a mean postloading follow-up of 43 months, and thus no differences were detected among the studied variables. On the contrary, the general linear model showed that longer (ie, length > 13.0 mm) and wider (ie, diameter > 3.75 mm) implants and implant type (Frialoc and XiVE TG) are correlated with a lower crestal bone resorption and thus a better outcome. Conclusion: Immediate loading of implants retaining a mandibular overdenture is a reproducible, predictable, and reliable method to deliver efficient return of function for totally edentulous patients. Keywords: general linear model, immediate loading, implants, overdenture