President Shimon Peres placed a wreath near the coffin, which was wrapped in a blue and white Israeli flag.
The body was driven to the Knesset from an army base near the hospital outside Tel Aviv where Sharon died on Saturday.
"The public will be able to pay its respects until 18:00 (16:00 GMT)," the prime minister's office said.
Thousands of Israelis are expected to pay tribute at the Knesset, police said.
A state memorial is planned for Monday with the participation of Israeli and world leaders, the prime minister's office said.
US Vice President Joe Biden, former British Prime Minister Tony Blair, Czech Prime Minister Jiri Rusnok, German Foreign Minister Frank-Walter Steinmeier and others will attend, it added.
Afterwards Sharon's body will be taken by military convoy for burial at his ranch.
One of Israel's most controversial figures, Sharon had been in a coma for eight years after a devastating stroke incapacitated him at the peak of his political power.