May 15 – The United States grants de facto recognition to the State of Israel, eleven minutes after it comes into existence, becoming the first country to recognize the Jewish state.
May 17 – The Soviet Union grants de jure recognition to the State of Israel, becoming the first country to do so.
May 15 – Four of the seven countries of the Arab League at that time, namely Egypt, Iraq, Jordan and Syria, backed by Arab volunteers invade the territory of the former British Mandate of Palestine and clash with Jewish forces. The resulting 1948 Arab–Israeli War lasts for 13 months.
May 14–18 – 1947–1948 Civil War in Mandatory Palestine: Operation Kilshon – Capture by Jewish forces of buildings abandoned by British troops to strengthen the Jewish military position in Jerusalem.
May 20 – The Syrian Army is blocked at kibbutz Degania Alef in the north, where local Jewish militia reinforced by elements of the Carmeli Brigade halted Syrian armored forces.
May 20 – Operation Balak begins with the objective of transferring arms from Czechoslovakia to Israel.
June 1 – The Irgun and the Provisional government of Israel sign an agreement for the dissolution of the Irgun and integration of its fighters into the Israel Defense Forces.
June 11 – The Irgun's cargo ship Altalena which carries weapons, medical equipment and 930 Jewish immigrants, sets sail from France towards Israel.
June 20 – Altalena reaches the coast of Israel. The Provisional government of Israel demands that all the weapons on board be handed over to it unconditionally, in accordance with the agreement regarding the integration of the Irgun into the Israel Defense Forces. The Irgun refuses to comply.
June 22 – A violent confrontation between the Israel Defense Forces and members of the Irgun occurs over the Altalena and David Ben-Gurion eventually orders the Israel Defense Forces to shell the Altalena, and it burns off the shore of Tel Aviv. Sixteen Irgun fighters and three Israel Defense Forces soldiers die in the fighting.
July 9 – The beginning of the Israel Defense Forces's Operation Dekel, which lasts until the July 18.
July 10 – Operation Danny: Israel Defense Forces Soldiers capture the strategically important airport at Lydda.
September 17 – The Lehi assassinates the Swedish diplomat Folke Bernadotte, who was appointed by the UN to mediate between the Arab nations and Israel.
September 22 – The Provisional State Council of Israel passes the Area of Jurisdiction and Powers Ordnance, 5708-1948, annexing all territory that Israel had captured since the war began, and declaring that from then on, any part of Palestine captured and secured by the Israel Defense Forces would automatically be annexed to Israel.
September 24–27 – 1948 Arab–Israeli War: Transport of Supermarine Spitfires acquired by Israel through Czechoslovakia.
October 15 – The beginning of the Israel Defense Forces's Operation Yoav, aimed at conquering the whole Negev desert.
October 21 – Battle of Beersheba: The Israel Defense Forces's Negev Brigade occupies Beersheba.
October 29 – The beginning of the Israel Defense Forces's Operation Hiram, aimed at conquering the Upper Galilee.
November 11 – Population Census is held in Israel, six months after its creation, to establish the population registry.
December 27 – The Israel Defense Forces starts Operation Horev, a wide scale attack against the Egyptian army in the Western Negev.
Other events:
July 22 – The Supreme Court of Israel is formed, with the first five judges of the court appointed after being recommended by the Minister of Justice and the interim government and appointed in a vote by the Provisional State Council.
August 17 – The Israeli lira replaces the Palestine pound and becomes the official currency of Israel when the Provisional State Council passes a law recognizing the new lira banknotes printed by the Anglo-Palestine Bank, which began arriving in Israel in July 1948, as legal tender.
September 14 – The Supreme Court of Israel is officially inaugurated in a ceremony in Jerusalem.