The woman from the Asyut province, to the south of Cairo, was hospitalized with a high temperature and bad cough on Saturday. She is believed to have contracted the virus after coming into contact with dead poultry.
Last week, an 18-month-old girl in northern Egypt's Manoufiya province was also diagnosed with bird flu.
Egyptian officials said that 23 deaths from bird flu have been recorded in the country since 2006.
As of March 11, a total of 411 bird flu cases had been registered worldwide since the virus was first detected in 2003, resulting in 256 deaths, according to the WHO.
Although there have been no incidences of human-to-human infection, experts fear that the bird flu virus may mutate into a form that could be easily transmitted from person to person, causing a global pandemic.