Blueberry stem galls in Pacific Northwest are often attributed to Agrobacterium tumefaciens. The disease also is associated with indole-3-acetic-acid (IAA) producing bacteria, as described on cranberry stem gall. Lack of studies makes it difficult to conclude whether these two types of bacteria could be the causal agent of stem gall of blueberry. Isolation methods in other studies failed to recover consistently tumorigenic bacteria from blueberry stem galls. In this study, two isolation methods were initiated and an effective one for recovering tumorigenic bacteria from blueberry stems was discovered. Micropropagating the infected blueberry plants enabled the isolation of the tumorigenic bacteria. When the isolates were tested with virD2 gene specific primers in PCR analysis, positives results obtained. Moreover, gall symptoms were obtained on blueberry ‘Draper’ experimentally with the tumorigenic isolates, using a revised inoculation procedure described in this paper. Sequencing results of the partial virD2 gene in this study suggest that the bacterium causing stem galls on blueberry is tumorigenic. It is similar in identity to the bacteria that cause crown gall disease on Rhododendron in Germany, which is known as a novel group of Rhizobium tumorigenes-like Agrobacteria.