Egyptian Foreign Minister Mohammed Kamel Amr announced the truce in Cairo hours before it came into effect at 9 p.m. local time (2 p.m. ET.)
Minutes after the deadline, celebratory gunfire, honking and cheering could be heard on some streets in Gaza City.
The truce seemed to be holding overnight, CBC's Susan Ormiston said from Jerusalem.
In Israel, Prime Minister Benjamin Netanyahu said he agreed to the ceasefire after consulting with U.S. President Barack Obama to allow Israeli civilians to get back to their lives. He said the two leaders also agreed to work together against weapon smuggling into Gaza, a statement confirmed by the White House.
"I realize that there are citizens who expect a harsher military action, and we may very well need to do that. But at present, the right thing for the state of Israel is to exhaust this possibility of reaching a long-term ceasefire," Netanyahu said in a statement.
Hamas spokesperson Osama Hamdan told CBC News his group believes the truce deal "will be good for both sides."
He added that Hamas would respect the terms of the ceasefire, which brings an end to eight days of fighting. "The task is not to fight. The target is to gain our rights back."
The UN Security Council also welcomed the ceasefire, saying in a statement Wednesday afternoon that it hoped the agreement would bring about "a sustainable and durable cessation of hostilities in Gaza and Israel" and lauding the efforts of Egyptian President Mohammed Morsi and others.
Egyptian officials helped mediate the truce, and will continue to play a key role by receiving "assurances from each party" that they are committed to the ceasefire. "Each party shall commit itself not to perform any acts that would break this understanding," the agreement says. "In case of any observations, Egypt — as the sponsor of this understanding — shall be informed to follow-up."
Foreign Minister John Baird said in a statement that Canada welcomes the ceasefire and "hopes that terrorist cells based in Gaza will abide by the terms of this agreement."
"We are deeply concerned about the loss of innocent lives on both sides," Baird said. He repeated Canada's support for Israel's "right to to defend itself against terrorism, which, in all its forms, must be wholly rejected by all peace-loving people around the world."
Fighting until deadline
There was a last-minute burst of fire before the truce took effect, according to Israeli authorities, as Palestinian militants fired several rockets. One rocket hit a house in the southern Israeli city of Beersheba, police said. No injuries were reported.
Meanwhile, Israeli shelling was reported in Gaza in the lead-up to the ceasefire deadline. There was at least one death and 25 injuries from the last Israeli attack before the deadline, Petricic said.
Earlier Wednesday, a bomb ripped through a public city bus in Tel Aviv, wounding 27 Israelis. A police spokesman said somebody threw the bomb onto the bus and detonated it from a distance. No arrests have been made, Brig.-Gen Yoram Ohayon said, noting that a number of people were seen running from the scene after the blast.
Hamas spokesman Sami Abu Zuhri called the bombing a "natural response to the Israeli massacres... in Gaza," but stopped short of saying Hamas was responsible for the attack.
The last time there was a bomb blast in Tel Aviv was in April 2006, when a Palestinian suicide bomber killed 11 people and wounded 70 others at a shawarma stand near the old central bus station.
Israeli aircraft also pounded Gaza with at least 30 strikes overnight, hitting government ministries, smuggling tunnels, a banker's empty villa and a Hamas-linked media office. At least four strikes within seconds of each other pulverized a complex of government ministries the size of a city block, rattling nearby buildings and shattering surrounding windows. Hours later, clouds of acrid dust still hung over the area and smoke still rose from the rubble.
In downtown Gaza City, another strike levelled the empty, two-storey home of a well-known banker and buried a police car parked nearby in rubble.
The last week of fighting has killed 161 Palestinians, including 71 civilians, and forced hundreds of thousands of people on both sides of the border to remain huddled indoors. Five Israelis were killed.
Washington blames Hamas
Washington blames Hamas rocket fire for the outbreak of violence and has backed Israel's right to defend itself, but has cautioned that an Israeli ground invasion could send casualties soaring.
The U.S. considers Hamas, which has killed hundreds of Israelis in suicide and other attacks, to be a terrorist group and does not meet with its officials. Canada also lists Hamas as a terrorist organization.
Hamas won Palestinian elections in 2006 and the militant group secured its hold on Gaza the following year as it beat back an attempted coup by gunmen from rival Palestinian faction Fatah, at the same time launching rocket attacks upon Israel before agreeing to an Egyptian-brokered ceasefire in 2008.
Israel launched its most recent offensive last Wednesday following months of rocket salvoes from the territory into southern Israel, which has endured attacks for the past 13 years.
For its opening salvo, it assassinated Hamas's military chief, then followed up by bombarding the militant-run territory with more than 1,500 airstrikes that initially targeted rocket launchers and weapons storage sites, then widened to include wanted militants and symbols of Hamas power.
Defying Israel's claims that they've been badly battered, the militants have so far fired more than 1,400 rockets at Israel, drawing upon newly developed and smuggled weapons to extend the reach of their attacks toward Tel Aviv and Jerusalem, Israel's largest cities. The number of Israelis within rocket range leapt to 3.5 million from one million.