A survey on the prevalence of heartworms, scabies and demodicosis of 1,011 pet dogs in 5 animal hospitals Jeonju area was peformed from June to October 2004. The result obtained from this experiment were summarized as follows; 1. The 1,011 pet dogs coming to help the animal hospital more than disease of pleonephritis 62($6.1\%$), enteritis 75($7.4\%$), dermatitis 62($6.1\%$), scabies 55($5.4\%$), heartworms 43($4.3\%$), tympanitis 41($4.1\%$), demodicosis 22($2.2\%$), gastritis 21($2.2\%$), fracture 9($0.9\%$), respectively. 2. The 307 examined pet dogs were heartworms antigen positive to 43($14.0\%$), Microfilaria 31($10.1\%$) and the kinds of mixed breeds 34 (antigen and Microfilaria 12), Jindo 19 (antigen 7, Microfilaria 6), respectively. 3. Heartworms antigen positive of examined 34 pet dogs mean ages 4.3 and general blood cell count mean of WBC $20.5{ imes}10^3/mm^3$, RBC $61.3{ imes}10^6/mm^3$ HGB $6.27g/d{ell}$ HCT $20.9\%$, PLT $13.0{ imes}10^3/mm^3$, MCV $33.2{mu}m^3$, MCH 39.4pg, MCHC $14.8g/d{ell}$, RDW $280.1\%$, MPV $9.2{mu}m^3$, respectively. but showed a few high normal value WBC, MCV, MCH and a low MCHC. 4. This experiment was 1,011 pet dogs to dermatitis 139($13.7\%$) of scabies 55($39.6\%$), demodicosis 22($15.8\%$), respectively.