The poll showed Obama leading McCain by eight points, 50 percents to 42 percent, McClatchy Newspapers reported.
The poll also found 1 percent of likely voters expressed support for independent candidate Ralph Nader, while 7 percent of respondents said they were still undecided.
McClatchy said if Obama wins Tuesday's presidential election with at least 50 percent of the popular vote he would be the first Democrat to do so since President Jimmy Carter garnered 50.1 percent in 1976.
The poll, conducted Thursday through Sunday, of 760 likely voters 18 has a margin of error of plus or minus 3.6 percentage points.
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