How is the government elected?
Based on a system of proportional representation, where voters select a party instead of a specific individual, Israeli elections have always resulted in coalition governments. To win an outright majority, a party would need to win more than 60 seats in the 120-member Knesset.
The minimum required for a party to win a Knesset seat is two percent of the total votes cast.
The prime minister is normally - but not always - the leader of the party that wins the most seats. He or she then negotiates with other parties to form a governing coalition.
In the 2009 election, although the incumbent prime minister's party, Kadima, won the most seats in the parliament, the Likud leader Binyamin Netanyahu was able to form a majority coalition government and become the new prime minister.
Why were elections called?
Netanyahu called for early elections in October 2012, saying he wouldn't be able to pass a "responsible" budget with his current coalition partners. He was pushing for deeper cuts to public spending.
If he hadn't called an early vote, the election would have happened in October 2013 - after the completion of the Netanyahu government's four-year term. In the past two decades, it has been rare for an Israeli government to finish a full term.
Who can vote?
Israeli citizens of all ethnic and religious groups above the age of 18 are entitled to vote. This includes Arab citizens of Israel, who generally vote in lower numbers than Jewish Israelis.
5,656,705 eligible voters can cast ballots at 10,128 polling stations, including 190 in hospitals and 57 in prisons. There are also 96 voting places at Israeli diplomatic missions abroad.
What are the election logistics?
There are 34 party lists competing for seats, reflecting a wide range of outlooks and beliefs. Prior to the elections, each party presents its platform and the list of candidates for the Knesset in order of precedence.
The Central Elections Committee, headed by a justice of the Supreme Court and including representatives of the parties holding seats in the Knesset, is responsible for conducting and supervising the elections.
Polls will open at 7:00am (0500GMT) and close at 10:00pm (2000GMT) on January 22. Election Day is a public holiday.
Who is in the current government?
Likud-Beiteinu, the governing electoral alliance led by Netanyahu, currently holds a combined 42 seats in the Knesset.
Likud ["The Consolidation"] first came to power in 1977 under the leadership of Menachem Begin, a former head of the Irgun armed paramilitary group. Yisrael Beiteinu ["Israel Our Home"], founded by Avigdor Lieberman in 1999, has policies further to the right of Likud and is seen by many as extremist.
Kadima ["Forward"], the party founded by former Prime Minister Ariel Sharon in 2005, holds 28 seats. It is led by Shaul Mofaz, who is seen as a centist. The party promotes a two-state solution with the Palestinians. It is not polling well in the upcoming election and may struggle to win a single seat.
Labour, led by Shelly Yachimovich, holds just eight seats, and is trying to focus its campaign on economic issues, rather than on security.
HaBayit HaYehudi ["The Jewish Home"] is set to make some of the biggest gains in this election. Currently it only holds three seats but the right-wing, religious party led by Naftali Bennett, a former special forces commander, has gained popularity.
In its first election, HaTnuah ["The Movement"] led by former foreign minister Tzipi Livni, says it supports a return to negotiations with the Palestinians and claims to be an alternative to Likud. It is expected to win about seven seats.
Led by TV host Yair Lapid, Yesh Atid ["There is a future"] is a new party that portrays itself as an alternative to the established groups. It is set to win more than six seats, according to polls.
Shas, a religious party comprised of Jews originally hailing from North African and Middle Eastern countries, currently holds 11 seats.
What are some other parties?
Yahadut HaTorah ["United Torah Judaism"], another religious party, caters primarily to Ashkenazi Haredi groups and holds five seats.
Meretz ["Energy"], a secular party newly led by Zahava Gal-On, is seen as pro-environment and left-leaning, and holds three seats.
Ra'am-Ta'al [an acronym for "The Arab Movement for Renewal"], an alliance primarily supported by Arab-Israelis, holds four seats.
Hadash [an acronym for "The Democratic Front for Peace and Equality"], a leftist party led by Mohammed Barakeh with support from Arabs and Jews, also holds four seats.
Balad [an acronym for "National Democratic Assembly"], a secular Arab nationalist party led by Jamal Zahalka, holds three seats.
The task of forming a government and heading it as prime minister is assigned by President Shimon Peres to the Knesset member considered to have the best chance of forming a viable coalition government in light of the results.
Parties remaining outside the government comprise the opposition. The Knesset member to whom the task is assigned has a period of 28 days to form a government. The president may extend this term by up to 14 days.