This study examined the validity of the four standard psychological paradigms that have been operationally defined within the CogState brief computerized cognitive assessment battery. Construct validity was determined in a large group of healthy adults. CogState measures of processing speed, attention, working memory, and learning showed strong correlations with conventional neuropsychological measures of these same constructs (r's = .49 to .83). Criterion validity was determined by examining patterns of performance on the CogState tasks in groups of individuals with mild head injury, schizophrenia, and AIDS dementia complex. Each of these groups was impaired on the CogState performance measures (Cohen's d's = -.60 to -1.80) and the magnitude and nature of this impairment was qualitatively and quantitatively similar in each group. Taken together, the results suggest that the cognitive paradigms operationally defined in the CogState brief battery have acceptable construct and criterion validity in a neuropsychological context.