Bovine immunodeficiency virus (BIV) which was grouped into the Lentivirinae of family Retroviridae, was known to be causing many immunodeficiency syndromes among cows. The BIV was studied worldwide during last several years for its importance in cattle industries but nothing was reported in Korea until now Thus we initially tried to study the existence of BIV in cattle around the Daegu·Kyungpook area by PCR related molecular techniques. As a prerequisite investigation for detecting Korean-type BIV, we had focused our aim into BLV infected cows because the BLV infected cows tend to show BIV infection with 5％ ranges. Hence we randomly sampled fresh bloods from 248 cows and bulls near the Daegu·Kyungpook area and collected peripheral blood monocytes (PBMC) from the sample bloods. After extracting genomic DNA from the PBMC, we subjected it to PCR and Soluthern blot analysis for BIV/BLV detection. Overall, 66.9% (81/121) of the cow PBMC samples turned out to be BLV positive by PCR and the result was reconfirmed by Southern blot analysis. The value was two times higher than the previously reported results of BLV infection in Korea. The significant difference was mainly due to 1) applying highly specific methods for BLV detection such as PCR 2) that BLV was continuously spreaded in the Daegu Kyungpook area without any notice during last ten years. We also tested the BLV positive samples with the same techniques for BIV detection. And we found some BIV positives among the lot 3C samples by PCR, which had showed 100% BLV positive.