A 53-year-old man with chronic lymphocytic leukaemia and multiple comorbidities presented with a 2-day history of increasing pain and swelling in his left leg following a minor trauma, associated with signs of systemic sepsis and worsening multiorgan failure. The clinical picture was consistent with necrotising fasciitis and he was taken to the theatre for an above-knee amputation. Blood and tissue cultures grewPseudomonas aeruginosaonly, which is very rare as a monomicrobial infection, with relatively few cases being reported in the literature. The combination of aggressive timely surgical intervention, broad-spectrum antibiotics and treatment on the intensive care unit yielded a successful outcome from this acute episode.