The aim of this study is to update the prevalence of dirofilarial infections in pet dogs. From the year 2010 to the year 2014, a total of 143 blood samples were collected from privately owned pet dogs in Novi Sad. All samples were examined by wet blood smears, the modified Knott test and heartworm antigen test. Circulating microfilariae of both Dirofilaria (D.) immitis and D. repens were found in dogs. Prevalence values for D. immitis and D. repens were 16.78% (24/143) and 18.88% (27/143), respectively. We report mixed infection with both parasites for the first time. Results of this study, compared with results of previous investigations, shows increase of infection with D. immitis and increase of mixed infection with both Dirofilaria species. Further investigations are required with higher number of samples to confirm these findings.