Leptospirosis is a worldwide zoonosis with the highest incidence in tropical regions. The reservoir animals, mainly mice and rats, excrete leptospira organisms in their urine asymptomatically. It is transmitted to human hosts either by contact with the infected urine or via contaminated water or soil during the work and recreational activities. The aim of the case reports is to point out to another potential source of leptospiral infection - domestic rats which have become favorite home pets in the last twenty years. Three patients with various severities of the disease and treated in 2005-2010 are reported. The patients most likely acquired the leptospiral infection from their pet rats.