Pontiac fever is a non-pneumonic, epidemic form of legionellosis. The symptoms are similar to flu: fever, tiredness, myalgia, arthralgia, headache, cough, sore throat and nausea. The incubation period is from 30 to 90 hours, approx. 36 h., the attack rate is high: 70-90%. There are no differences in sex and age of ill people, the same number of women and men or children were affected. Unfortunately, ill children symptoms might be differ: higher fever (40 C), lack of leukocytosis with left shift, shorten incubation period. The etiological agents are usually bacteria: Legionella pneumophila sg 1, sg 6 and Legionella micdadei. Diagnosis of Pontiac fever is after finding seroconversion or high titre of antibody to Legionella in serum samples or L. pneumophila antigen in urine sample. Pontiac fever cases are frequently found during epidemiological investigation of legionnaires' disease case. Detection of Pontiae fever might be a marker of contaminated with Legionella environment and a risk of live-threatened pneumonia.