Ticks are hematophagous ectoparasites belonging to the phylum Arthropoda. There are two groups of ticks: the hard ticks (Ixodidae) and the soft ticks (Argasidae). Hard ticks which belong to the genus Ixodes are the most important for the transmission of tick – borne microorganisms to humans in Europe. The life cycle of a tick consists of four stages: egg, larva, nymph, and adult. The blood meal that the tick performs on the mammalian host is essential for the maturation of the tick. During the blood meal, the tick will aspirate pathogenic microorganisms and further transfer it to its life cycle (transstadial transmission) or to new generations (transovarial transmission). Ixodes ticks usually look for three different hosts in their life cycle for three blood meals (three hosts life cycle). In times when they are not feeding, the tick rests in nature. Ticks are important vectors of microorganisms in humans. The most important diseases are Lyme borreliosis and Tick-borne meningoencephalitis, but they also transmit other diseases such as rickettsiosis, tularemia, human ehrlichiosis and anaplasmosis, babesiosis and others. LB with the development of EM and KME with the development of morbus minor which defines as short-term febrile illness and morbus major which occurs after a short asymptomatic period with no fever with the development of neurological symptoms. In addition to the clinical picture, the diagnosis is most often confirmed by indirect diagnostic methods, mostly serology. The seasonal incidence of these diseases corresponds to the seasonal peaks of tick activity in spring and autumn, although this phenomenon is subject to susceptible variations depending on the climatic conditions in the current year. Most tick bites will be asymptomatic, because not all ticks are infected with pathogens. Also if a host has a good host immune system, it will easily defend itself from the tick-borne microorganism; yet some bites will result in the development of clinical picture of the disease. It is important to recognize it and treat in time with medication in order to prevent late manifestations and possible complications.