A diamond-shaped red crystal on a white background is to join the Red Cross and the Red Crescent as an emblem for ambulances and relief workers.
Israel could use the new symbol to operate as an ICRC member
Geneva Convention member states voted by a two-thirds majority for the symbol, ending a decades-old row and opens the way for Israel to join.
Israel had been denied entry because its Red Shield was not approved.
Relief workers and ambulances bearing the Red Cross or Red Crescent symbols are protected under international law.
A spokesman for the Swiss government told reporters it was unfortunate that the crystal had not been adopted by consensus.
The Red Shield of David - or Magen David Adom - was not recognised by the 1949 Geneva Conventions, and Arab states had blocked attempts to find an alternative symbol.
The new "crystal" - a hollow red diamond on a white background - is regarded as being free from religious, national or cultural connotations.
Israel has said it is ready to use it for missions outside the country's borders - as set down by the Geneva Conventions.
The vote in Geneva was delayed by wrangling between Syria and Israel over access for Syrian medical staff to the Golan Heights.
Syria said it was prepared to approve the crystal but wanted Israel to allow the Syrian Red Crescent access to the plateau, which Israel seized in the closing stages of the 1967 Six-Day War.
Syrian Minister of State Bashar al-Shaar told reporters that Syrians in the Heights "suffered terribly through lack of medical services".
Israel's ambassador to the UN in Geneva, Itzhak Levanon, ruled out letting Syria have access because there were no diplomatic relations with Damascus.