Mother won the business after a final shoot-out with Publicis. The pitch, which did not involve an intermediary, kicked off in June.
New Look has worked with a number of smaller agencies in the past, but brought its creative in-house last year and then launched a press and outdoor campaign across the UK, Ireland and France in April.
The ads featured on small billboards and ran alongside a magazine campaign planned by Trinity Communications.
New Look also retained Dare as its social media agency after a pitch late last year. The agency was charged with devising a campaign to engage with blogging communities and social network users.
In June, New Look reported a 17.7 per cent rise in profits for the year to the end of March 2010.
New Look's core consumers are 16- to 30-year-old women. However, in 2001, the retailer diversified into men's clothing, which has been rolled out to more than 20 per cent of its stores. It has 1,000 outlets across 13 countries.