Answer: Yes. If your Canadian donors have U.S. income, they can generally claim any gifts to U.S. charities that would be allowed on a U.S. return. In general, Canadians can claim the eligible amount of their U.S. gifts up to 75% of the net U.S. income they report on their Canadian return.
However, some Canadians may be able to claim the eligible amount of their gifts to certain U.S. organizations up to 75% of their net world income. In order to qualify for this tax treatment, they must live near the border in Canada throughout the year and commute to their principal workplace or business in the United States. Finally, that employment or business must be their main source of income for the year.
You can find more information on the subject at the Canadian Revenue Agency located at http://www.cra-arc.gc.ca