The 4.4 percent unemployment rate matches a decade low. The highest unemployment rate was in El Centro, Calif., at 19.2 percent.
"Companies may be taking a more cautious approach to hiring", said Nariman Behravesh, chief economist at IHS Markit.
More than 400,000 people stopped looking for work entirely. But as May's numbers show, not all of them are finding jobs; some are giving up on their search.
But manufacturers, retailers and governments lost workers last month. Through May, employers added an average 162,000 jobs to payrolls each month, a slower pace than the 187,000 jobs added monthly in 2016. The health care overhaul the administration favors is being reworked in the Senate.
Employment in health care rose by 24,000 in May. According to that report, job growth was strong among construction firms and in professional and business services. Since last October, this sector has added 47,000 jobs, for something under 8,000 jobs per month.
"Today's jobs number is disappointing, but the overall trend is still very positive and the unemployment rate continues to decline", said Tony Bedikian, managing director of global markets at Citizens Bank. Construction added 11,000 jobs.
The labor force tumbled by 429,000 people in May, while the household survey of employment showed a decrease of 233,000 people. Also, job growth in March and April combined were 66,000 less than previously reported, after the Bureau revised its figures. May's projected increase would be in line with this year's 185,000 average monthly job growth.
Expectations for a bumper jobs report had mounted after ADP, the US's largest private payroll processor, announced employers had added 253,000 jobs in May - well above the 180,000 economists had been expecting.
Although he described the jobs report as "underwhelming", Shaffer said the labor market remains strong and there are no signs of a looming recession eight years into the current economic expansion.
The labor force participation rate fell slightly to 62.7 percent during President Donald Trump's fourth full month in office, continuing to trend at its lowest rate since the late 1970s.
One calendar quirk that may have depressed wage gains in May was that the 15th of the month - when workers who are paid semi-monthly get their checks - fell on the Monday after the survey week, which includes the 12th. Over the year, average hourly earnings have risen by 2.5 percent, the same growth rate as in April.
As the economy continues to expand and reaches a point where almost everybody who wants a job can find one - what economists call full employment - companies should have to start raising wages to attract new workers.
The Federal Reserve increased its benchmark interest rate a quarter of a point during its March 14 meeting, which was the second such increase in three months.
The leisure and hospitality industry added 31,000 net new jobs in May, down from 58,000 the previous month.