Over the next year, additional persons in Maryland may be at risk for exposure of toxic Pfiesteria or morphologically related organisms. These persons may present with a variety of memory and other behavioral complaints. This paper examines the kinds of complaints that persons with a documented Pfiesteria-related syndrome have compared to a nonexposed control group. The exposed group was more likely to report difficulties with concentration, forgetfulness, prospective memory, and information overload as well as feelings of confusion, bewilderment, and uncertainty as direct effects of toxin exposure. The exposed group was also more likely to report feeling uneasy, on edge, nervous, and shaky, which is probably a reaction to their newly acquired cognitive deficits and uncertainty about their recovery. In contrast, retrograde memory loss, disturbances of language or social behavior, depression, anger, hostility, or diminished activity levels are not symptoms that exposed persons are likely to report.