Purpose: To test whether there is a difference in success rates between immediately, early, and conventionally loaded implants. Materials and Methods: All randomized controlled clinical trials (RCTs) of root-form osseointegrated oral implants having a follow-up of 6 months to 1 year comparing the same osseointegrated root-form oral implants loaded immediately (within 1 week); early (between 1 week to 2 months); or conventionally (after 2 months) were eligible. An exhaustive search was conducted with no language restriction on January 15, 2007. Outcome measures were prosthesis failures, implant failures, and marginal bone levels measured on intraoral radiographs. Screening of eligible studies, quality assessment, and data extraction were conducted in duplicate. Authors were contacted for any missing information. Results were expressed as random effects models using weighted mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals. The statistical unit of the analysis was the patient. Results: Twenty RCTs were identified, and 11 trials including a total of 300 patients were included. Six trials compared immediate versus conventional loading, 3 early versus conventional loading, and 2 immediate versus early loading. None of the meta-analyses revealed any statistically significant differences. Conclusions: It is possible to successfully load dental implants immediately or early after their placement in selected patients, although not all clinicians may achieve optimal results. A high degree of primary implant stability (high value of insertion torque) seems to be 1 of the prerequisites for a successful immediate/early loading procedure. More well-designed RCTs are needed. Priority should be given to trials comparing immediately versus early loaded implants. These trials should be reported according to the CONSORT guidelines (www.consort-statement.org). Keywords: dental implants, early loading, immediate loading, randomized controlled clinical trial, systematic review