Lyme disease, a tick-borne infection caused by the spirochete Borrelia burgdorferi, involves many organ systems. Three clinical stages of involvement have been described; patients with the disease may have cutaneous, arthritic, neurologic, or cardiac symptoms, or a constellation of manifestations. Specific antibody testing and antibiotic agents are available for Lyme disease, but a high index of suspicion must be exercised to recognize atypical manifestations.