Definition
The Parties Law, passed in 1992, defines a party as "a group of persons associated in order to advance political or social goals by legal means, and to bring about their representation in the Knesset by elected representatives."

Registration requirements
A party must be registered with the party registrar, must have rules of procedure by which it functions, and certain institutions which ensure its well ordered functioning. Under the law a party cannot be registered if "there is in its goals or activities, explicitly or implicitly, one of the following: 1) the denial of the existence of the State of Israel as a democratic Jewish state; 2) incitement to racism; 3) a reasonable basis to believe that the party will serve as a front for illegal activities. According to Amendment 19 to the Basic Law: the Knesset of 1996, only a party can participate in elections to the Knesset. In fact, a list can include more than one party, or a party (or parties), plus non-partisan individuals and groups.

Israel's parties
Israeli political parties are an extremely heterogeneous group, whose large number is primarily a result of the electoral system, but also the historical background of the state and its complex social structure.

Some of the parties and political blocs in Israel have roots in the Yishuv, the pre-state Jewish community, or in the World Zionist Organization. These include the social-democratic Israel Labor Party, with roots in the historical Mapai; the liberal-rightist Likud, with roots in the Revisionist Movement and the General Zionists; the National Religious Party, with roots in the Mizrahi Movement; and the fundamentalist Agudat Yisrael, which emerged from a movement with the same name. The origins of these parties are reflected in their ideological platforms and their historical frames of reference.

On the other hand, new parties have constantly appeared on the scene, and then usually disappeared. Some of these parties have represented ethnic groups and others more radical political positions than the existing parties. Several parties developed around charismatic leaders.