The US Labor Department says the consumer price index in May rose 3.3 percent from a year earlier.
The rate is 0.1 point lower than the previous month and a decline for the second consecutive month, easing concerns about inflation to some extent.
The market expected a rise of around 3.4 percent.
By item, the prices of used vehicles went down 9.3 percent from the same month last year, while transportation costs rose 10.5 percent, housing costs increased 5.4 percent, and prices for eating out were up 4.0 percent.
The index excluding food and energy, whose prices fluctuate widely, rose 3.4 percent year-on-year. The figure is down 0.2 points from a month earlier and lower than market expectations.
The Federal Reserve places importance on the index as an indicator to assess inflation.