M2M triumphed in a pitch against MindShare, OMD, Starcom and the incumbent agency, Vizeum.
It is understood that the brand, which predominantly uses outdoor advertising created in-house, is planning to up its UK spend this year.
The decision comes amid a Europe-wide media planning and buying review, which is being held on a market-by-market basis. Mango is approaching media agencies across the continent.
The clothing chain is planning a uniform media strategy as it expands into new markets such as Italy, Australia and China. It has also recently opened new stores in Vienna, Paris and London.
Advertising for Mango's 2006 spring collection features the model Bianca Balti. Previous campaigns have starred Mick Jagger's daughter Elizabeth Jagger and the supermodels Naomi Campbell, Christy Turlington and Claudia Schiffer.
Mango opened its first store in 1984. It is owned by the Spain-based Punto Fa, the second-largest exporter in the Spanish textile sector.
M2M declined to comment on the appointment and Mango did not return calls.