In this study, a dog brought with a complaint ol turning around was evaluated. Clinical examinations revealed a marked weakness in the femoral pulsation, eodema developed in the tarsal and carpal regions and wounds in the skin. It was observed that the haematocrit values increased by 66%. In thick blood smears, in ava rag e 7-8 Di-roflaria larvae were seen in each viewable area when viewed with the 100X objective. In the analysis ol the blood: the levels of urea, albumin, glucose, creatinin, ALT. ALP and LDH were found to be in the normal range. In the necropsy, marked dilatations in the right chamber of the heart were observed and 20 mature Dirofilaria immitis (ranging 18-20 cm) were seen. Brain looked hyperemic and bulgy and menings appeared cloudy. Hislopathological examinations showed that oedema, fibrin and thickining in the menings and numerous erythrocytes in the blood vessels of the menings. In these regions, there were condense mononuclear cell and neutrofil leucocyte infiltrations. The brain tissue under the menings involved with the infection (substantia grisa region only), severe necrose, condense mononuclear cell, neutrofil leucocyte infiltrations and also dense gitter cell proliferation were detected. In the brain tissue. Staphylococcus aureus was identified by bacteriological examinations. In conclusion, by carrying out clinical, biochemical, heamatological, microbiological and histological examinations, the case was diagnosed as drofilariasis complicated with purulent meningoencephalitis.