After five consecutive monthly declines, the index rose in July. But confidence returned to its downward trend in August, despite gains in stock markets.
The index, which assigns 1985 a base value of 100, fell from 65.4 in June to 60.6, the Conference Board said.
The monthly Consumer Confidence Index is based on a survey of 5,000 households.
"Consumers were more apprehensive about business and employment prospects, but more optimistic about their financial prospects despite rising inflation expectations. Consumers' assessment of current conditions was virtually unchanged, suggesting no significant pickup or deterioration in the pace of growth," said Lynn Franco, director of the board's Consumer Research Center.
In the August survey, respondents indicating business conditions are "good" rose from 13.7 percent to 15.2 percent. Respondents indicating conditions declined were unchanged at 34.4 percent.
Respondents indicating jobs were easy to find fell from 7.8 percent to 7 percent, while those who indicated jobs were hard to find fell from 41 percent to 40.7 percent.