Lyme disease is an infection caused by a spirochete, B.burgdorferi which affects many organs in the body. This infection is carried by ticks in the Ixodes group, 50.000 cases have been reported between 1982-1992 in the United States. In mid-Europe, 4000-5000 cases were recorded each year after 1988. In our country, the total number of collected cases are about 20. After isolation of the agent of this disease in 1982, disease mechanisms and biology of this spirochete have been extensively studied. Our review aims to present the agent and explain the microbiological diagnosis of this infection which can mimic many diseases from rheumatoid arthritis to epilepsy and from heart disease to meningitis and which may cause sequela if it is not treated properly with antibiotics.