This study deals with the preliminary investigation of the malarial and other avian blood parasites (Sporozoa: Haemosporida) of sylviid warblers from south of Belarus. Traditional parasitology is based mainly on morphological identification parasites from blood films. PCR-based methods have improved the detectability of haemosporidian infections in birds. Our objective was to PCR diagnostics of simultaneous haemosporidian infections in naturally infected bird. The material was collected from alive birds. All birds were ringed and released after experimental work. Approximately 50 μl of whole blood for molecular assays were collected in SET buffer. Blood films were examined microscopically. Genomic DNA was extracted from the blood by using standard method of proteinase K digestion followed by phenol-chloroform extraction. The PCR analysis was used to detect Plasmodium and Haemoproteus spp. presenting in blood. A fragment of approximately 480 base pairs were amplified using PCR-primers to locus of mitochondrial cytb gene belonging to the genera Haemoproteus and Plasmodium. Only one from all examined birds were revealed as a host for blood parasites both by microscopic examination and mtDNA PCR-analysis. Such combination of approaches of microscopy and molecular methods provide new opportunities for diagnosis of parasitic diseases during light infections, which dominate in birds in nature. The fact that some birds (during breeding period) harbored parasites from genus Haemoproteus and Plasmodium is indicate possibility of active transmission of the avian blood parasites at the study site.