Sick building syndrome, characterized by upper respiratory irritative and central nervous system symptoms, is poorly understood. Building ventilation problems are frequent, although causative agent(s) are unknown. Few studies have addressed clinical characterization of symptomatic building occupants. Employees from two sites underwent standardized evaluation including medical history, physical examination and screening neurologic and neuropsychologic testing while acutely symptomatic. Both symptomatic and asymptomatic individuals were evaluated when one of the sites was evacuated. Baseline evaluation results for this group were available for comparison. Symptoms of both work forces mirrored those reported in the literature. General medical examination abnormalities were few and minor, while neurologic and neuropsychologic examinations documented mental status, cerebellar, and neurobehavioral deficits. There were statistically significant changes from baseline. Abnormalities were self-limited. Controlled evaluations of symptomatic sick building occupants should be performed to verify these findings.