Growth in non-manufacturing has slowed in three of the past four months. In May to June, the Purchasing Manager's Index slipped from 53.7 percent to 52.1 percent.
With numbers above 50 indicating growth, June marked the 30th consecutive month of growth in the U.S. service sector.
The index for new orders in June also slowed slipping from 55.5 to 53.3. The employment index, however, climbed from 50.8 to 52.3, as growth picked up from close to the break-even point.
Both the new orders and the production indexes have remained positive for 35 consecutive months, as the production index fell from to 55.6 to 51.7.
The employment index, which has shown growth for six consecutive months, showed faster gains with the index rising from 50.8 to 52.3.