For the first time, DNA from human pathogenic R. helvetica (7.5%), R. monacensis (6.1%), A. phagocytophilum (1.4%), E. muris (0.7%), F. tularensis (2.7%) and Babesia sp.EU1 (0.7%) has been detected in Romania. The tick Ixodes ricinus is one of the most important vectors of a large variety of pathogens of veterinary and medical importance in Europe (1). The most prevalent I. ricinus-borne infection in humans in Europe is Lyme borreliosis, a multisystemic disorder caused by spirochetes of the Borrelia burgdorferi sensu lato complex (2) . This complex comprises at least 12 species worldwide, B. afzelii, B. garinii and B. valaisiana being present in Romania (3). Patients bitten by ticks can be infected by many other pathogens, besides Lyme borreliosis, such as other bacteria (Anaplasma spp., Francisella spp., Coxiella burnetii, Bartonella spp., Rickettsiae spp. and Neoerhlichia mikurensis), parasites (Babesia spp., Theileria spp.) and arboviruses (TBE, CCHF, EYA …) (1). The symptoms induced by such pathogens are often non-specific and highly diverse which complicates disease diagnosis. In Romania, only limited data is available on diseases transmitted by ticks but cases of Lyme disease and tick borne encephalitis (due to TBEV) have been identified (3). Little is known about the importance of these diseases and none of the other tick-borne pathogens present in Europe has been detected so far. One recent study indicated that I. ricinus is the most abundant tick in Romania and is widespread throughout the country (3). As 50% of Romania constitutes a suitable habitat for I. ricinus development, the importance of tick-borne diseases is probably underestimated. The first step to evaluate the circulation of these potential human pathogens is their detection in ticks in previously unexplored areas. The aim of this study was to estimate the prevalence of the main tick-borne human pathogens known to circulate in Europe in ticks collected in Romania.