Plesiomonas shigelloides is a rare cause of invasive infection, most clinically significant isolates being from the gastrointestinal tract of animals and man. Recently it has been implicated as an increasing cause of opportunistic infections. We report a case of P. shigelloides septicaemia and pleural effusion in a patient with pre-existing alcoholic liver disease. This case serves to illustrate the possible role of P. shigelloides as an opportunistic pathogen in a compromised host especially where there is co-existing liver disease.