The purpose of the current study was to examine neuropsychological functioning in a group of never-medicated first-break adolescents with psychosis. It is the first report of cognition in a sample of adolescents with psychosis in which all patients were drug-naive. Twenty-nine adolescent patients (mean age = 16.07; SD = 2.00; 15 male and 14 female patients) experiencing their first psychotic episode and 17 age-matched and sex-matched normal volunteers (mean age = 16.88; SD = 2.39; 9 male and 8 female subjects) were recruited and assessed with a neuropsychological battery. Measures of attention, memory, language, executive functioning, perceptual motor processing, and motor speed were obtained. Psychiatric symptomatology, estimated verbal IQ, and parental socioeconomic status were also determined. Patients with psychosis were significantly more impaired than normal volunteers; effect sizes were greatest in the areas of executive functioning, attention, and memory, and significantly smaller in areas of language, perceptual motor processing, and motor speed. The pattern was not altered when differences in verbal IQ and parental socioeconomic status were controlled. Sex and age interactions indicated that younger male patients were particularly impaired. The findings demonstrate neuropsychological deficits in adolescents with psychosis and suggest that cognitive deficits are core symptoms in psychotic disorders.