To detect cattle with higher bovine leukemia virus (BLV) proviral loads (PVLs), which present an increased risk of both horizontal and vertical transmission, using an inexpensive method, we developed a direct PCR test using diluted blood for the PCR template (dilution D-PCR). Dilution D-PCR had an intentionally low sensitivity and detected only cattle with high PVLs and not low PVLs. The sensitivity and specificity of the dilution D-PCR were compared with the two major previously reported methods, BLV-CoCoMo-qPCR and EC Key. BLV-CoCoMo-qPCR is a TaqMan probe-based real-time PCR method and is known to have high sensitivity but be high cost. On the other hand, EC Key is based on the number of lymphocytes and is known to be inexpensive but have low sensitivity. More than 99% (133/134) of samples from middle- and high-risk cattle identified by BLV-CoCoMo-qPCR were positive using the dilution D-PCR test. All 15 samples that were negative using EC Key but identified as high-risk using BLV-CoCoMo-qPCR were positive using dilution D-PCR. According to these results, dilution D-PCR has the sensitivity and specificity to detect middle- and high-risk cattle equivalent to BLV-CoCoMo-qPCR testing. We believe that dilution D-PCR is useful for detecting a major BLV infectious source at a low cost.