While still comfortably above the 50 mark separating growth from contraction it was below a preliminary estimate for 53.3.
A PMI covering the services sector dropped to 55.1 from April's one-year high of 56.2, below the 55.9 flash reading.
A manufacturing PMI released last week showed the downturn in factory activity deepened as demand slumped despite prices falling.
"The services sector is being supported by the strong labour market, rising wages and a tourism sector that is flourishing throughout Europe," said de la Rubia.
"The latter is confirmed by the new export business PMI, which includes tourism-related demand and remained near its series peak in May."
Persons:
Cyrus de la Rubia, Jonathan Cable, Toby Chopra
Organizations:
P Global, April's, Hamburg Commercial Bank, PMI, European Central Bank, ECB, Thomson
Locations:
Hamburg, Europe