In total 1,005,861 people travelled through the airport in May, up by 11.1% compared to the same month last year.
This means the airport has celebrated fifteen consecutive months of record breaking growth.
Long-haul routes continued to experience the greatest rise in demand with 16.5% passenger growth compared to the same month last year, while short-haul routes saw a 10.5% growth rate year on year.
Paul Kehoe, chief executive officer at Birmingham Airport, said: “To be hitting the one million passenger mark in May is fantastic news for the airport.
“It shows us that the new airlines and routes we have recently introduced are proving popular with our passengers.
“We are now entering the busy summer season and so we hope that these consecutive record breaking figures will continue going forward.”
Scheduled traffic accounted for 89% of the total passenger volume for May with charter traffic making up the remaining 11%.
Scheduled traffic saw an increase of 21.6%, with significant year-on-year passenger growth to Heraklion, Reykjavik, and Dubrovnik.
Charter destinations with significant growth were Fuerteventura, Gran Canaria and Lanzarote.