Symposium LL, 'Scientific Basis for Nuclear Waste Management XXXVI', was held November 25-30 at the 2012 MRS Fall Meeting in Boston, Massachusetts. This Symposium continues to set the research agenda in the field of radioactive waste management, charting the development of waste processing, conditioning, packaging and disposal. Symposium XXXVI featured 77 presentations, delivered over four days during the 2012 MRS Fall Meeting, from participants in Australia, Austria, Finland, France, Japan, Russia, Spain, Sweden, Switzerland, the United Kingdom, and the United States of America. Sessions reported on advances in glass and ceramic wasteforms, conditioning of technetium, management of spent nuclear fuel, and geological disposal, plus a special joint session with Symposium HH, on radiation effects in nuclear materials. Each paper provides a snapshot of the exciting recent developments in each of these areas and the international progress toward achieving the safe, timely and cost-effective management and disposal of radioactive wastes.