A 25-year-old man has died in the Red Sea port city of Jeddah and a woman of 69, who suffered from tuberculosis and anaemia, died in Mecca, also western Saudi Arabia, the health ministry said.
At the same time, 35 new cases of the severe respiratory disease have been recorded, raising the number of sufferers in the Gulf state over the past two years to 396, the world's highest tally.
Yesterday, US health officials said the first case of MERS has been confirmed in the United States.
And last week, Egypt recorded its first infection after a person who arrived from Saudi Arabia tested positive.
Public concern in Saudi Arabia over the spread of MERS has mounted after the resignation of at least four doctors at Jeddah's King Fahd Hospital who refused to treat patients for fear of infection.
Some research has suggested that camels are a likely source of the virus.
MERS is considered a deadlier but less-transmissible cousin of the SARS virus that erupted in Asia in 2003 and infected 8,273 people, nine percent of whom died.
