The Department of Energy of the United States of America (USDOE) has been studying the Yucca Mountain site in Nevada for more than 15 years to determine whether it is a suitable place to construct an underground repository for US spent nuclear fuel and high-level radioactive waste of commercial and military origins. A number of performance assessments have been carried out over the past decade by the USDOE, the latest of which is the Total System Performance Assessment supporting the site recommendation process (TSPA-SR) of December 2000. This report presents the results of the jointly organised NEA-IAEA international peer review of the TSPA-SR, performed upon the request of the USDOE. The review was carried out by a team of ten international specialists.