Babesiosis is an infectious, tick-borne disease caused by the parasitic species of Babesia. Transmission via blood transfusion or transplacental infections are much rarer. Most cases of human babesiosis occur in the United States, whereas only single cases have been reported in Europe, including Poland. Anaemia due to erythrocyte haemolysis, which in more severe cases may result in multiple organ dysfunction syndrome and death, particularly in immunocompromised patients, is a typical sign of babesiosis. Immunocompetent patients are asymptomatic or develop mild infection accompanied by fever, osteoarticular pain and erythrocyturia. The diagnostics of babesiosis should be considered in patients with flu-like symptoms who live or are temporarily residing in endemic areas as well as in patients diagnosed with other tick-borne diseases. Final diagnosis should be based on microscopic examination of thin blood smears (Wright or Giemsa staining followed by examination under oil immersion) or PCR-based amplification of the babesial genetic material. Treatment with atovaquone and azithromycin or clindamycin and quinine usually allows for a complete recovery and prevents complications. Severe cases of babesiosis require exchange transfusion. The infection is frequently combated by the immune system without the use of antibiotics in patients with mild or asymptomatic babesiosis. The prevention of babesiosis primarily involves protective measures that minimize the exposure to ticks, which are the only source of infection.