Lyme borreliosis is a multisystem infectious disease affecting mainly the skin, nervous system, joints and heart. It is caused by spirochetes of the Borrelia burgdorferi sensu lato complex which are transmitted by ticks. The diagnosis of Lyme borreliosis is based primarily on typical clinical symptoms and signs with serological confirmation. Antibiotic therapy is beneficial for all manifestations and treatment refractory cases are rare. The diagnosis "chronic Lyme borreliosis" is increasingly being misused for all conceivable medically unexplained symptoms.