Material samples from 40 ticks, including 30 Ixodes ricinus and 10 Dermacentor reticulatus ticks were tested for presence of Borrelia burgdorferi infection with indirect immunofluorescence assay (IF) and polymerase chain reaction (PCR). Sensitivity of PCR in terms of minimum detectable number of in vitro cultivated spirochetes was a reproducible amplification when 50 spirochetes were added to the PCR mixture. The assay sensitivity was lower for B. burgdorferi in ticks and it was estimated on minimum 100 bacterial cells. B. burgdorferi DNA (16S rDNA) has been found in 10 I. ricinus ticks. Immunofluorescence has been observed in Immunofluorescence has been observed in 32 samples derived from 22 I. ricinus and 10 D. reticulatus ticks both incubated with immune serum for B. Burgdorferi as well as with normal serum. Our results indicate that due to very low specificity IF is not a usefull method for testing of tick material.