Thousands of Palestinians have taken to the streets of the West Bank and Gaza in memory of the "catastrophe" which befell them when Israel was founded in 1948.
Nakba Day marks the anniversary of when hundreds of thousands were forced to flee or were expelled from their homes in the war that accompanied Israel's declaration of independence.
Loud sirens blared across the West Bank city of Ramallah at midday to mark the anniversary, with people observing a minute's silence ahead of a huge rally in the Clock Square.
Throughout the city, cars were decked out with black flags carrying a picture of a key and the word "return" in English and Arabic to remember homes they left or were forced from which are now inside Israel.
Hundreds also gathered at the nearby Ofer military prison, and at the Qalandiya crossing between Ramallah and Jerusalem, where there were minor clashes with Israeli troops, who fired tear gas and rubber bullets to disperse the crowd.
Further north, several thousand people gathered in Nablus city centre waving flags and calling for the right of return.
But they also hailed the successful end of a mass hunger strike by Palestinian prisoners in Israeli jails, which was resolved late yesterday.
This year's anniversary was to have been a protest over the ongoing mass hunger strike by 1,550 prisoners, most of whom had been refusing food for between four and 11 weeks.
But in a last-minute development, the dispute was resolved when prisoner leaders signed a deal with Israel, agreeing to end their fast in exchange for an easing of their conditions.
Thousands more demonstrated in the southern city of Hebron which was turned into a sea of red, white, black and green Palestinian flags, with protesters also celebrating the successful end of the prisoners' strike.
In annexed east Jerusalem, clashes broke out in the early morning between police and stone-throwing demonstrators in the east Jerusalem neighbourhood of Issawiya.
And in downtown Gaza City, thousands joined a march organised by the ruling Hamas movement, AFP correspondents said.
A general strike was being observed by merchants across the West Bank and Gaza, as well as in the main Arab towns and cities inside Israel.
Israeli police, who with the army are routinely placed on high alert for Nakba Day, confirmed there had been scuffles in Issawiya, at Rachel's Tomb near Bethlehem and in Qalandiya checkpoint. But only four people have been arrested in the mostly peaceful protests.
The army also had little to report, saying there were several incidents of stonethrowing at Halhul near Hebron, but that the events for the most part were proceeding quietly.
It was a stark contrast with Nakba Day last year, when Israeli troops in the north fired on hundreds of protesters who tried to cross the Lebanese border and the ceasefire line on the occupied Golan Heights, leaving at least 11 people dead and hundreds wounded, according to UN figures.
Similar protests near the border in northern Gaza also left more than 120 people injured by gunfire.
More than 760,000 Palestinians - estimated today to number 4.8 million with their descendants - fled or were driven out of their homes in 1948.
Around 160,000 Palestinians stayed behind and are now known as Arab Israelis. They now number about 1.3 million people, or some 20% of the population.
