Euro RSCG London won the business on a project basis in May this year.
However, La Senza held a pitch for the account following the arrival of Sarah Hawkins, the new marketing director, in August.
Karmarama will create a Christmas campaign encouraging men to buy La Senza gifts for their partners, followed by a national TV, print, outdoor and digital campaign for spring 2011.
La Senza's previous activity included a summer press and outdoor campaign to promote its lingerie and swimwear ranges. The campaign, through Euro RSCG, emphasised La Senza's design and fit and used the strapline: "Fabulously fitted."
Separately, Karmarama has won the advertising account for the Southbank Centre, the arts centre that comprises the Royal Festival Hall, Hayward Gallery, Queen Elizabeth Hall, Purcell Room and Poetry Library.
The agency was appointed after a pitch and will work on a brief to position the Southbank Centre as the world's leading cultural destination. Kaper, Karmarama's PR agency that launched earlier this year, has been appointed to work on brand PR around the campaign.
In addition, Karmarama will develop products for the Southbank Centre retail outlets. The Southbank Centre is the UK's largest arts centre and is situated on the south bank of the Thames.