Ahmad Al Shareef, 80, was pronounced dead on Satruday morning, after his heart failed, the sources said.
Al Shareef is patient number 90 who died in Gaza due to the Israeli siege on the coastal region.
Israel has placed the Gaza Strip under siege since June 2007; two weeks ago the Israeli army stepped up the Siege and sealed off the Gaza strip borders totally, leaving the 1.5 million residents lacking food, medicine, and fuel supplies.