There has been renewed interest in the idea that attentional dysfunction may underlie autistic symptomatology (e.g., Bryson, Wainwright-Sharp, & Smith, 1990; Dawson & Lewy, 1989a, 1989b). Existing research indicates problems with overfocused attention (Lovaas et al., 1971; Rincover & Ducharme, 1987), and with shifting attention between sensory modalities (Courchesne et al., 1990). These phenomena were examined further by using Posner's (1978) visual orienting task with a group of high-functioning autistic adolescents and adults, and matched normal controls. Our results indicate that autistic people have difficulty processing briefly presented cue information. Evidence of problems disengaging and shifting attention within the visual modality was also provided. The findings can be seen as consistent with previous behavioral, autonomic, and electrophysiological research which has revealed impairments in the registration, processing, and response to external stimuli.