The assessment of the changes in knowledge about aging is essential to the development of aging courses and curricula. The present instrument was designed to reliably and validly measure various areas of information about aging. An item pool was gathered by examining texts and printed materials and consulting with persons specializing in gerontology. Existing instruments were also surveyed and types of items, as well as areas covered, were examined. The first draft of the instrument was administered to both undergraduate and graduate classes in gerontology in the fields of nursing, sociology, social work, and residents in internal medicine. The initial draft was also administered to several undergraduate and graduate classes in courses unrelated to the field of gerontology. The resultant 100-item Iowa Aging Inventory was developed to have four 25-item subscales: financial, medical and biological, psychological, and social/living environment aspects of aging. Preliminary data show the inventory to be reliable and valid. The Iowa Aging Inventory, along with its subscale items and answers, is included. (Author/PN)