The Conference Board's measure of CEO confidence rose to a reading of 55 in the second quarter from 30 in the first quarter-- readings of more than 50 reflect more positive responses than negative responses.

Almost 55% of CEOs expect economic conditions to improve in the next six months. And 32% said economic conditions have improved now compared with six months ago.

"CEOs are considerably more optimistic than last time about the short-term outlook," said Lynn Franco, director of The Conference Board Consumer Research Center. "However, their assessment of current conditions, while also improved, suggests the economy remains weak."

The measure's survey includes approximately 100 CEOs.