The business is believed to be worth about £500,000. It will involve an in-hotel campaign that will launch in May across Europe and Japan, targeting current guests.
Online booking is an increasingly important channel for the hotel group.
In March last year, Hilton International joined forces with rival hotel chains Hyatt Corporation, Marriott International, Six Continents Hotels and Starwood Hotels to form the Hotel Distribution System, a venture that will market hotel rooms over the internet through multiple online sites.
The appointment marks the first time that Hilton has worked with LIDA, the below-the-line arm of M&C Saatchi.
The hiring is not thought to affect WWAV Rapp Collins, which handles Hilton International's through-the-line business and media buying across the UK and Ireland.
WWAV was appointed in December 2001, resulting in incumbent agency The Morgan Partnership going into liquidation.
In November 2002, Hilton blamed a 9% fall in quarterly pre-tax profits on a "challenging" trading environment and added that its global hotel operations produced "widely varying performances".
No one from LIDA was available to comment on its appointment.