A repository of bio-specimens that includes organs from 700 deceased workers employed at the first nuclear weapons facility "Mayak" and donations of blood, buccal cells, and tissues removed at the time of surgery and/or biopsy from the members of the Mayak cohort undergoing medical treatment or diagnostic procedures has been established at the Southern Ural Biophysics Institute, in Ozyorsk, Russian Federation. The autopsied tissues include formaline-preserved organs, paraffin blocks, and histology slides. For all, occupational, dosimetry, and detailed medical information is available. For 359 individuals, information on malignant tumors, i.e., lung (171), stomach (51), liver (28), and intestine (19), as well as 32 cases of leukemia, are available. External gamma exposures are known for 95% of the 700 autopsies, of whom 560 were exposed to protracted doses exceeding 0.5 Gy, with known maximum annual doses ranging from 0.01-0.5 Gy for about 46%, and annual doses exceeding 0.5 Gy for 48%. Plutonium body burden is known for 73%, of which 40% had body burden greater than 1.5 kBq, and 15% of individuals had body burdens greater than 11.85 kBq. Newly collected specimens include frozen lymphocytes, EBV-immortalized B-cells, frozen erythrocytes, and DNA as well as frozen tumors. Donations were obtained to date from more than 1,600 individuals. For these donors external doses of exposure exceeded 0.5 Gy for 83%, and plutonium body burden exceeded 1.48 kBq for 30%. A Web site describing the Repository that also includes forms for tissue requests can be accessed at http://www.subi.ru/RHTR.