The demonstrators, led by representatives of factions and accompanied by high-ranking government officials, carried flags and shouted slogans in support of the thousands of Palestinian prisoners in Israeli jails.
They marched through the streets of Gaza and Ramallah to the Palestinian Legislative Council, carrying pictures of their imprisoned family members and symbolically tying their hands together with chains.
They called on Palestinian parliament members and ministers, human rights organisations and the international community to make the release of prisoners a priority.
The parliament convened a special session to address the plight of the prisoners on Monday.
One of the demonstrators, 27-year-old Leila Dabbagh, said she had not seen her fiance for the past five years because he had been in an Israeli jail.
Itimad Abu Narra carried a picture of her son Fouad, who she said has been in prison since 2001.
Young and innocent
"The prisoners issue is the most important of the Palestinian national issues. Most of them are young and did nothing - their crime is just being Palestinian. We are hopeful that this issue will be addressed soon and they will be released," Abu Narra said.
Yusuf Risqa, the Palestinian minister of information, said his government plans to send a delegation of freed Palestinian prisoners on a tour of Arab countries to talk about their plight.
Addressing the rally, he urged Palestinians to be patient in the face of economic sanctions and said the government would not neglect its responsibilities.
About 8,000 Palestinians are in
"Remember, 'Verily with hardship, there is ease'," he said, quoting a verse from the Quran.
About 8000 Palestinians are held in Israeli prisons or detention centres, including 370 minors and 103 women, according to the Palestinian prisoner's rights and support group, Addammeer.
More than 750 are being held without charge or trial.
The Israeli human-rights group B'Tselem says the majority of Palestinian inmates are political prisoners who have been arbitrarily imprisoned or detained under the broad banner of "security".
"If these same standards were applied inside Israel, half of the Likud party would be in administrative detention," the group's report said.
Some want the release of
prisoners to be a national priority
Addammeer says Palestinians are subjected to the highest rate of incarceration in the world.
Since the beginning of the occupation of Palestinian territories in 1967, Israeli forces have imprisoned more than 650,000 Palestinians - about 20% of the total Palestinian population, and 40% of all Palestinian men.
Amnesty International criticises the conditions in which detainees are held, saying many of them suffer from medical negligence, routine beatings, position torture and strip searches.
Photos used in this story are from Laila El-Haddad.