Erythema migrans (EM) is an early localized form of Lyme borreliosis (LB). EM appears 3-30 days after tick bite and presents as annular homogenous erythema, marked from unaffected skin. Typical EM has more than 5 cm in diameter, but there are reports of mini-EM in literature. Moreover, multiple or bullous EM are described. Diagnosis is based on clinical picture. In treatment antibiotics must be used. The aim of this paper was to draw attention to still existing problem of LB in Poland, not only in endemic areas and to the necessity of proper diagnosis, early implementation of antibiotics. It may prevent from late form of LB development, which may lead to irreversible damage, especially in nervous system or joints. EM presence in history increases the probability of subsequent LB forms such as neuroborreliosis or arthritis. Otherwise, symptoms may be misinterpreted, as they resemble the other in the course of more common diseases.