The poll, conducted earlier this week, found 46 percent of those surveyed had a positive view of the country's former top diplomat compared to 33 percent with a negative image, the Journal reported Thursday.
In April, 56 percent had a positive view. Clinton stepped down as secretary of state on Feb. 1.
Polls have found Clinton to be the top Democratic candidate for president in 2016 should she decide to run.
Two of her hypothetical Republican opponents did not fare so well.
The poll found Texas Sen. Ted Cruz with a 19 percent approval rating and a 30 percent negative approval rating. Most, 35 percent, had no opinion or didn't know his name.
Some 33 percent viewed New Jersey Gov. Chris Christie favorably, while 17 percent saw him negatively. Another 26 percent had no opinion or didn't know his name.
Only 1 percent of those surveyed had never heard of Clinton or didn't know who she was.
The decline in her favorability rating was greatest among independents, Democrats and people between the ages of 18 and 34. In April, Clinton garnered a 53 percent approval rating from younger respondents between 18 and 34 years old. This month, her approval in that demographic had fallen to 38 percent.
In the same period, her approval by independents fell from 46 percent to 35 percent; among Democrats, it fell from 88 percent to 76 percent.
Some 800 people were interviewed for the survey, which was conducted Oct. 25-28. No margin of error was given.
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