Patients with frontal lobe lesions were compared to controls matched for age and education on several tests of sustained attention. One was a simple reaction time task requiring subjects to respond whenever they saw an "X', one was a Continuous Performance Test that required subjects to respond to an "X' but refrain from responding to other letters, and one involved reading a story and responding to a specified target. Patients with right frontal lesions showed longer RTs and missed more targets than control subjects for all three tests. In addition, right frontal patients got worse with time on the CPT. These results suggest a special role for the right frontal lobe in sustaining attention over time.