During the month, the airport handled 4.7 million passengers and 339,000 tonnes of cargo, showing year-on-year increases of 4.1% and 1.8%, respectively.
Flight movements set a new monthly record of 31,040, representing a 6.1% increase compared to the same month last year.
The growth in passenger traffic in May was due to 7% year-on-year growth in visitor traffic and 10% growth in Hong Kong resident traffic.
Passenger traffic to/from South East Asia and mainland China performed particularly well.
The growth in cargo throughput last month was driven mainly by exports and trans-shipments, which were up 1% and 4%, respectively, from a year ago.
During the month, cargo throughput to/from North America outperformed other key regions.
Stanley Hui Hon-chung, CEO of the Airport Authority Hong Kong, said: “We are delighted that monthly flight movement has reached a new record high, beating the previous record of 30,799 set in December 2012.
“Although increasing demand is posing greater challenges, HKIA is dedicated to maintaining our high service standards.
“We recently reconfigured arrangements at the Meeters and Greeters Hall, setting up extra stanchions and rearranging the waiting area to provide more circulation space for passenger flow.
“From small improvements to large-scale facility developments, we are committed, as always, to providing travellers with a delightful airport experience.”
Over the first five months of 2013, passenger traffic increased 4.1% to 23.9 million, while cargo volume also grew 2.2% to 1.6 million tonnes.