The rate was down from 11.6 percent in April. The agency said the number of people in employment rose to 57.1 percent during May, an increase of 0.1 of a percentage point.
Youth unemployment, meanwhile, is steady at 36.9 percent.
There were 299,000 more people in work in May than in the same month last year, Istat said, while 175,000 fewer were claiming unemployment benefit.
Some 22.677 million people were employed in May, and 2.95 million were unemployed.