Agrobacterium species have been previously implicated in the development of clinical disease. We report what we believe to be the first case of ascites caused by Agrobacterium tumefaciens in a cirrhotic patient. Since the correct diagnosis was made only after laparoscopy-guided collection of specimens from two different tissues, we suggest that Agrobacterium may be an underdiagnosed pathogen in clinical situations in which tuberculosis is considered to be the cause of high-protein ascites.