The paintings of the New York School painter, Mark Rothko, are aging at an accelerated rate. The combination of his experimental techniques and materials, and the vulnerability of the paintings to environmental degradation have contributed to this deteriorating process. By briefly assessing the three mural projects that Rothko painted between 1958-1965, including their formulation and specific histories, factors which have precipitated the changes in the paintings can be established. Ultimately this information can be applied to Rothko's paintings in general, emphasizing preventative measures for their maintenance and treatment. -- AATA