Schizophrenia-spectrum disorders may reflect the genotype for schizophrenia. One such disorder, Schizotypal Personality Disorder (SPD), was examined as a function of family history of schizophrenia. Clinical profiles and neurocognitive functioning were evaluated in 25 schizotypal subjects (10 SPD with schizophrenic relatives and 15 SPD without schizophrenic relatives), and in 24 normal controls. The primary finding is that vigilance performance was similarly impaired in both SPD groups. An additional neurocognitive impairment, comprehension of grammatical constructions, was observed only in the SPD group with schizophrenic relatives. Of interest, the clinical profiles of the two SPD groups did not differ significantly. These results suggest that schizotypal personality disorder is associated with a continuum of neurocognitive vulnerability that increases as a function of family history of schizophrenia.