Lyme borreliosis (Lyme disease), a tick-borne spirochetal illness, has multisystemic involvement and is rapidly increasing in certain areas of the United States. Although its neurologic manifestations are becoming increasingly well recognized, its psychiatric presentations are not well known. The first section of this paper will provide an overview of Lyme borreliosis and a review of the relevant neuropsychiatric literature. The second section will provide clinical descriptions of some common neuropsychiatric symptoms as well as a discussion of the problems typically faced by patients with this illness. Guidelines to assist the clinician in working with these patients will be presented.