Chicken production is positioned as an important source of meat in the whole world. Approximatively 60 billion chickens are produced annually in the whole world. Parasitic diseases, like coccidiosis, represents a constant challenge in raising domestic and wild animals, because of persistent challenges, antimicrobial resistance, economic losses, as well as negative impact over production indicators. Apicomplexan parasites of the genus Eimeria are considered to be a great risk for avian production, because it is the agent that causes avian coccidiosis (Blake D.P., Clark E.L. et al., 2015), causing failure in achieving daily weight gains and their mortality (Ramos D., 2019). At the same time, coccidiosis is recognized as the parasitosis with the greatest economic impact on poultry production, annual damage constituting 3 billion dollars in the world poultry industry (McDonald and Shirley, 2009). The investigations regarding the determination of eimeria species in wild (pheasant, quail) and domestic (hen, turkey, guinea fowl) birds were carried out in the Laboratory of Parasitology and Helminthology, Institute of Zoology of the University of State of Moldova. Samples were collected from various areas of the Republic of Moldova during the years 2020-2022. Coproscopic examinations were carried out, using flotation methods with supersaturated sodium chloride solution (Darling method), through which Eimeria oocysts were identified. The material collected was examined using the Novex Holland B ob. 20-40 WF 10x DIN objective /20mm microscope. As a result of the parasitological research carried out on wild birds (pheasants) in the 45 collected biological samples, an infestation with 4 species of eimeria was established: Eimeria colchici, Eimeria duodenalis, Eimeria dispersa and Eimeria phasiani. The species Eimeria dispersa is common to turkeys, quails and partridges. In the quails in the 32 collected biological samples, the infestation with the following species was established: Eimeria bateri, Eimeria coturnicis, Eimeria dispersa and Eimeria usura. In domestic birds (hens) 6 species of Eimeria were recorded in the 122 collected biological samples: Eimeria acervulina, Eimeria brunetti, Eimeria maxima, Eimeria mitis, Eimeria necatrix and Eimeria tenella. The most pathogenic of these eimeria species are considered to be Eimeria necatrix and E. tenella, which cause high mortality. Infestation with the species Eimeria numidae was established in guinea pigs in 17 biological samples. In turkeys from the 54 biological samples investigated, 4 species of eimeria were recorded: Eimeria adenoeides, Eimeria dispersa, Eimeria meleagridis and Eimeria gallopavonis. Therefore, infection with an only species of Eimeria is rare in natural conditions, mixed infections being usual. Whereas combating coccidiosis is very hard to realise and very expensive, preventive measures are the only effective and economical ones. Biocontrol measures can minimize the spread of sporulated oocysts. Practicing strict biosecurity is essential for poultry farmers.