Purshouse replaces Caroline Baxter, who left in the summer to freelance, and will work mainly on the Essential Selection section of the magazine.
She said PROs should contact her with details of 'middle-market, accessible brands for women in their 20s, sold in boutiques and department stores, from Top Shop to Chloe. The clothes must be available nationally.'
Her boss, Cosmo fashion director Shelly Vella, added: 'I have spent the past couple of years trying to refresh fashion in Cosmo, which was stuck in a 1980s rut. We wanted to make it more affordable.
Meanwhile, Cosmo features editor Laurel Ives has quit the NatMag title to join Hachette's Elle as deputy editor.