a test designed to assess the adequacy of knowledge about specific words, presumed to be well established in long-term storage, was administered to 5 alcoholic Korsakoff patients, 3 post-trauma amnesics, and 5 normal controls. The 400 question true/false test tapped knowledge of basic and obscure attributes and functions of 25 noun-concepts. The data indicate that traumatic amnesics made more total errors than Korsakoff amnesics, who in turn made more errors than normals. However, Korsakoffs made a greater proportion of errors on basicknowledge items than the other groups. It is concluded that semantic organization is impaired in both amnesic groups, although differently. The post-trauma error pattern suggests a uni-factor deficit while the Korsakoff pattern suggest a multifactor deficit.