The phenomenon of catatonic-like states in people with autistic spectrum disorders is discussed in the context of current knowledge about catatonia as it occurs in severe mental illness and, less frequently documented, in conjunction with developmental disorders. The existing literature on catatonic-like states in people with autistic spectrum disorders is summarized, and it is suggested that such states are not directly comparable with the existing concepts of catatonia. A concept of 'autistic catatonia' is outlined in terms of both its phenomenology and its possible aetiological and maintaining factors. A case study is presented that examines this phenomenon from a cognitive neuropsychological perspective, together with implications for everyday management. The implications of this work for both research and clinical practice are discussed.