The agency won the business following a pitch against undisclosed agencies.
Hall Moore has been briefed to develop the advertising for the launch of a new website platform in 2007 in a bid to increase brand awareness.
Ciaran Lally, the general manager for ebookers.com in the UK and Ireland, said: "We are delighted to be working with Hall Moore CHI for 2007, in what will be a key year in the development of ebookers.
"We have a number of product developments planned for next year, and Hall Moore CHI will be instrumental in helping us reach our goals."
Warren Moore, the creative partner of Hall Moore CHI, added: "It's very exciting to be involved at this stage in ebookers' development. It's an impressive company in a rapidly growing market, which makes it a great opportunity for us to be a part of."