Lyme disease is a chronic tick borne disease, caused by spirochetes B. burgdorferi. The condition influences mostly on skin, nervous system, skeletal system and circulatory system. Recently more and more reports of so called "Post Lyme syndrome (PLS)" have appeared. PLS is a new clinical, diagnostic and therapeutic problem connected with patients with a history of Lyme disease (with proper antibiotic treatment). The symptoms of Post Lyme Syndrome may be present throughout months or even years. These are: fatigue, widespread musculoskeletal pain, dysmnesia, concentration difficulties. Pathogenesis of PLS is unknown. It is suspected that main factors responsible for PLS are: slow regression of infection, its turning into chronic process and permanent destruction of tissues or induction of immunological response against B. burgdorferi. Diagnostic of PLS is difficult. Mostly results of serological examination are negative. In some cases antibodies titer is positive as a sign of past disease. So far there is no causative treatment of PLS. Antidepressants, painkillers and anti-inflammatory medicines are recommended.