The victims were identified as a 41-year-old expat who was working in the health sector in Riyadh and a 79-year-old Saudi who suffered from chronic illnesses and who came into contact with a patient stricken by the virus in the northeastern city of Hafr al-Baten.
Saudi Arabia is the country worst hit by MERS, which has killed 50 people globally, according to a statement published by the World Health Organisation on August 30.
Experts are struggling to understand MERS -- Middle East Respiratory Syndrome -- for which there is still no vaccine and which has an extremely high fatality rate of more than 51 percent.
It is considered a cousin of the SARS virus that erupted in Asia in 2003 and infected 8,273 people, nine percent of whom died.
Like SARS, MERS is thought to have jumped from animals to humans, and it shares the former's flu-like symptoms -- but differs by also causing kidney failure.
According to research published this month in the American health journal Emerging Infectious Diseases, MERS was transmitted to humans from bats. But a study in the Lancet found the virus could have come from camels.