Background: Early loading of implant-supported prostheses in the edentulous mandible is widely accepted, but do the clinical results replicate those of delayed loading? Purpose: The aim of this study was to evaluate clinical outcome and patient satisfaction with early or delayed loading in patients treated with fixed prostheses, using three different implant systems. Materials and Methods: One hundred and nine consecutively treated patients received 490 implants supporting fixed prostheses; 82 patients with Brånemark System® implants (Nobel Biocare AB, Göteborg, Sweden), 16 with Astra Tech® implants (Astra Tech AB Dental Implant system, Mölndal, Sweden), and 11 with ITI® MonoType® implants (ITI Dental Implant System®, Institute Straumann AG, Waldenburg, Switzerland). Prostheses were placed within 2 to 3 weeks in 55 patients; 54 patients underwent a two-stage procedure. Data were collected from patient records and radiographs; 83 patients attended a clinical examination and received a questionnaire. Results: All patients had fixed prostheses at follow-up with a mean observation time of 3.5 years. Cumulative survival rates (CSRs) were 92.5% of prostheses and 94.4% of implants for early loading, and 98.0 and 97.9% for delayed loading. The mean radiographic bone loss after the first year was small, and at 5 years less than 0.2 mm for both groups. With early loading, significantly more prostheses (p < .05) needed adjustment or replacement. Conclusion: Statistically significantly more prostheses needed adjustment or replacement in the early group. The present study suggested lower CSRs for prostheses and implants in the early loading group after 5 years; the difference was not statistically significant. Larger study samples are needed to verify statistically small differences between treatment techniques.