These are the first reported cases in the Middle East
Israel has confirmed its second case of swine flu, in a 47-year-old man who recently returned from Mexico.
The man is in Meir hospital in the town of Kfar Saba, where he presented complaining of a sore throat.
Tests earlier also showed a young man recently returned from Mexico had contracted the virus. He is in Laniado hospital in Netanya.
In Mexico, 152 people are thought to have died from the disease, but so far there have been no deaths elsewhere.
Both the infected men in Israel are in quarantine and are expected to make a full recovery - as most sufferers around the world have, except in the case of Mexico.
Swine flu is a respiratory disease thought to spread through coughing and sneezing
Symptoms mimic those of normal flu
Good hygiene like using a tissue and washing hands thoroughly can help reduce transmission
These two diagnoses are believed to mark the first confirmed cases of swine flu in the Middle East. The World Health Organization has warned it has "pandemic" potential.
The second man has not yet been named but the first is 26-year-old Tomer Vagim, who complained of flu symptoms after returning from Mexico on Friday. A relative of his is also under observation, hospital officials said.
One Monday, Israel's deputy Health Minister Yakov Litzman, who belongs to an ultra-Orthodox Jewish sect, said the outbreak should be renamed "Mexican flu" in deference to Jewish and Muslim sensitivities over pork.
Swine flu is a respiratory disease, caused by influenza type A which infects pigs. There are many types, and the infection is constantly changing.
Until now it has not normally infected humans, but the latest form clearly does, and can be spread from person to person - probably through coughing and sneezing.