Efforts in developing and testing new drugs for the treatment of the cognitive impairment associated with Alzheimer's disease (AD) represent a major programmatic activity of the National Institute on Aging (NIA) but are now hindered by the lack of access of many investigators to animal testing facilities. The present paucity of any compounds which can uniformly slow or reverse the progression of the disease, ameliorate the symptoms, or prevent the disease requires that every effort be made to facilitate the development and testing of new compounds. The need to develop compounds for other aging related diseases such as osteoporosis is also apparent. Additionally, the advent of Positron Emission Tomography (PET) imaging agents for assessing brain beta-amyloid and other pathophysiological features of AD requires toxicological testing of these agents prior to human studies. However, there are still gaps in our overall effort to facilitate the development and testing of new compounds. Specifically, resources are needed by investigators who are developing new compounds so that the potential adverse toxicological activity of the compounds can be evaluated before they can be taken into clinical trials. This is a very expensive process and is beyond the resources of almost all investigators. NIA program staff have been contacted by investigators who have compounds that they believe seem promising for the treatment of Alzheimer's disease and that they would like to take into clinical trials, but they do not have the resources to have the mandatory toxicological screening done.