Edgard Celestin, a spokesman for Haiti's Office of Civil Protection, said three people were missing and 42 others sustained injuries, The Miami Herald reported.
Haitian and humanitarian officials were still assessing the storm's impact.
Some areas of the mountainous southern region remained isolated from assessment teams trying to evaluate the loss of crops and homes, the Herald said.
"We are still collecting information," said George Ngwa, communications leader for the U.N.'s Office for the Coordination of Humanitarian Affairs.
Haitian Prime Minister Laurent Lamothe, who visited several communities in the capital Sunday with President Michel Martelly, said the disaster reinforced the need to boost resettlement efforts for people still living in tent villages since a devastating earthquake in 2010.
Haitian officials said at least 2,346 homes damaged and 335 were destroyed.
Humanitarian officials said the biggest concern is over crop loss and Isaac's impact on a cholera epidemic that has killed more than 7,000 Haitians, the newspaper reported.
On Monday, Doctors Without Borders reopened a 275-bed Cholera Treatment Center in Carrefour, a Port-au-Prince suburb.
"We still have two months of hurricane season," Myrtha Kaulard, World Food Program's representative in Haiti. "In rural areas, we need not to underestimate the fact that some communities are isolated because beyond the collapsed bridge there are entire households that lack all possible access."