Previous research has shown that total sleep deprivation produces impairment in sustained attention and vigilance especially if the deprivation period is greater than 48 hours. However little is known about the effects of sleep deprivation on performance of tasks considered to be measures of higher cortical functioning such as tests of cognitive flexibility and the capacity to shift from one response set to another. One current hypothesis is that sleep deprivation of a shorter duration (34-36 hours) adversely affects higher cortical function while effects on attention and vigilance tasks are relatively mild. Performance on an intelligence test, a test of sustained attention and tests designed to measure higher cortical function were compared in a group of 29 subjects who underwent 34-36 hours of continuous sleep deprivation and 32 normal sleeping control subjects. No significant group performance differences in the hypothesized direction were noted on any measure. One night of total sleep deprivation does not appear to impair performance on tasks that are designed to assess higher cortical functioning.