The present study was conducted in order to get the relationship of heartworm, Dirofilaria immitis and eosinophils in blood of Jindo dogs. Blood samples were taken from 141( man 31, womam 110) of yellow, 44 ( man 17, woman27) of white Jindo dogs in Jindo area. The results obtained in this study were summarized as follows : 1. There were no significant differences of the hematological values in comparison with others reported values, but the mean corpuscular hemoglobin concentration and the number of eosinophils were high in comparison with other reported values. 2. The mean values of total white blood cell count(P<0.05), neutrophil(P<0.05) and monocyte(P< 0.05) were that the yellow dogs and a tendency toward fisher values than the white dogs, but no significant differences were observed. 3. Age-related differences were detected for the total erythrocyte count(P<0.05), hemoglobin content (P<0.001), PCV(P<0.001) and the number of eosinophils(P<0.001). 4. The direct and indirect eosinophil counts were increased with age, there were no significant differences of the values between two groups. 5. Dirofilaria immitis was found in 34(18.4%), increased with age and were relatively significant differences in areas of the 185 Jindo dogs. 6. Survey for hematological values of Dirofilaria immitis infected dogs with direct and indirect method, mean values of eosinophil were 2,788/ ${mu}l,$ 3,021/ ${mu}$l, respectively. They showed that eosinophil had a tendency toward higher values than others, but others were no significant differences.