A woman in her 60s from north Worcestershire has died from Legionnaires' disease. The woman, from Redditch, was admitted to the Alexandra Hospital in the town at the end of August.
Another woman from the area, who is also in her 60s, remains seriously ill with the disease.
Health authorities still do not know how the two people caught the illness and their domestic water supply will be tested.
The symptoms of Legionnaires' disease are similar to flu but it is not passed from person to person.
Hereford and Worcester Health Protection Agency is asking anyone who is concerned to contact NHS Direct or their GP.
Two people died from the disease during an outbreak in Hereford last November.