The number of people registered for unemployment benefits dropped to 131,290, down by 4,561 from the end of April, the state secretariat for economic affairs (Seco) said in a report released on Monday.
The number of people actively seeking work dropped to 185,012, 5,355 fewer than a year earlier.
But the unemployment rate last month remained higher than the 2.7 percent figure registered in May 2012, Seco noted.
The rate dropped or remained the same in all of the cantons, with the highest rate recorded in Geneva (5.5 percent, unchanged from the previous month) and the lowest in Obwald (0.9 percent, unchanged).
The biggest reduction was recorded in Valais, where the rate tumbled to 3.7 percent from 4.1 percent, followed by Graubünden (1.9 percent, down from 2.2 percent).
The jobless rate in Zurich fell in May to 3.1 percent from 3.2 percent in April, while dropping in Bern to 2.2 percent (down from 2.3 percent), to 3.6 percent in Basel-City (down from 3.8 percent) and to 4.9 percent in Vaud (down from five percent).
For Seco's complete report (in French, German and Italian) click here.