NSW Health confirmed this morning the man in his eighties from Potts Point died from the infection after becoming unwell in late June.
One person is still in hospital, whilst the remaining five patients have returned home.
All seven who were infected were residents of Potts Point.
South Eastern Sydney Local Health District and the City of Sydney confirmed they are still investigating the source of the outbreak.
A statement said none of the patients were known to each other, but it is believed they may have been exposed to a common source of infection.
What is Legionnaires’ disease
Legionnaires’ disease cannot be spread from person to person, and is caused by infection with the Legionella bacteria.
Common sources of infection include cooling towers on top of large buildings, which can spread the disease if the water source becomes infected.
Symptoms include fever, chills, cough and shortness of breath; in serious cases, it also could lead to pneumonia.
Dr Vicky Sheppeard of the South Eastern Sydney Local Health District said the department had sent requests to building owners and residents in the area as they look to find the source of the outbreak.
“The District has requested building owners disinfect their cooling towers on two occasions since the investigation began in June,” Dr Sheppeard said.
“People who have recently been in Potts Point and develop these symptoms should see their GP or go to a hospital emergency department.”
