Objective: To evaluate three-implant-retained mandibular overdentures after 3 years in terms of success rates, maximum occlusal force (MOF), marginal bone loss around implants (MBL), patient satisfaction, and quality of life (QoL). Method and Materials: Twenty-three edentulous adults with maxillary complete dentures who received threeimplant- retained mandibular overdentures with ball or bar attachments by the same surgeon over a 1-year period were evaluated 3 years after overdenture loading. Subjects were asked to grade their three-implant-retained mandibular overdentures on a visual analog scale and to complete the short-form Oral Health Impact Profile (OHIP-14) to evaluate satisfaction and QoL. MBL was evaluated using panoramic radiography. MOF with and without implant support was recorded using a strain gauge. Overall success was measured by absence of mobility, peri-implant radiolucency, pain and paresthesia, and progressive MBL. Results: The overall success rate of implants was 100%. MBL around center implants was lower than around implants on the right and left sides (P = .001 and P =.03, respectively). MOF without implant support was lower than with implant support (P =.001). There was no association between attachment type and either MBL, MOF, satisfaction, or QoL (P > .05). Conclusion: The excellent outcomes for three-implant-retained mandibular overdentures indicate that, regardless of attachment type, three-implant- retained mandibular overdentures opposing complete dentures are a successful treatment option for edentulous adults. Keywords: dental implant, mandibular overdenture, marginal bone loss, maximum occlusal force, patient satisfaction, quality of life