The Labor Department said Tuesday that job openings fell 3 percent to a seasonally adjusted 3.75 million.
Total hiring jumped nearly 5 percent to 4.4 million. And the number of people quitting their jobs increased 7.2 percent to 2.25 million.
More hiring and quits are a sign of a dynamic job market. Most workers quit jobs when they have a new position or are confident they can find one. More quits are therefore a good sign.
Still, overall hiring and quits are at about the same levels they reached in February and are below pre-recession figures. Total hiring topped 5 million in most months before the recession began in December 2007.
Monthly quits were typically around 2.8 million before the recession.
The job market remains very competitive for those looking for work. There were 3.1 unemployed workers, on average, for each open job in April. In a healthy economy, the ratio is 2 to 1.
And the drop in openings suggests that job gains may not pick up from their current modest pace in the coming months.
Employers added 175,000 jobs in May, a solid month of hiring that nearly matched the average gains of the past two years. The unemployment rate ticked up to 7.6 percent from 7.5 percent, but only because more Americans began looking for work last month. That's a sign many were more confident they could find jobs.
Openings have risen much faster than total hiring since June 2009, when the recession ended. The number of available jobs has increased 58 percent since then, but total hiring has increased only 22 percent.
That's a sign companies are slow to fill the jobs they have posted. Many employers have become more selective and cautious about hiring since the recession. Some may not be offering enough pay to attract the candidates they need. Other companies, particularly in information technology and manufacturing, say they can't find enough qualified workers.