This study sought to produce a cognitive profile of herpes simplex encephalitis (HSE) survivors from a large group of definitively diagnosed, acyclovir-treated participants. Results from 22 adults who underwent a battery of neuropsychological tests indicated anterograde memory dysfunction to be the most severe and common deficit (although the variation was great), with less severe and less frequent impairments in the areas of retrograde memory, executive functions, and language functioning. Overall, neuropsychological outcome was unimpaired in six participants, mildly impaired in thirteen, moderately impaired in one, and severely impaired in two. Older participants and those with a lower level of consciousness before the start of treatment produced poorer scores on certain aspects of cognitive outcome (p< 0.05). A significantly better cognitive outcome was found in participants for whom there was a short delay (fewer than 5 days) between symptom onset and acyclovir treatment compared with those participants for whom there was a longer delay. The two children in the study had disparate results on most tests, the exception being those assessing memory functioning on which both children had scores at population norms. On a naming task designed to explore category-specific knowledge deficits, the adults as a group made more errors on pictures of living things than nonliving things (matched pair-wise for word frequency and visual familiarity), although this difference disappeared on a smaller subset of pictures also matched for visual complexity.