This in-vivo study aimed to investigate the load on the working-side implant and on the edentulous distal mucosa of the nonworking side in a mandibular implant-retained overdenture (MIR-OVD) anchored to 2 implants by either a ball- or a clips-and-bar attachment. Three female patients were provided with duplicate dentures anchored in the 2 ways. Strain on the implant was investigated using a strain-gauged abutment, and load on the mucosa was measured using a suitably placed load cell. Ball attachments appeared to provide greater stability to the MIR-OVD, since load was more evenly distributed onto the distal mucosa of both sides. When the MIR-OVD was bar-anchored, axial load on the working-side abutment increased. Keywords: ball attachments, bar, implants, load, overdenture, strain gauges