The 10-month-old will be modelling designer swimwear on the cover of the Dolores Cortes US catalogue and star in the designer's 2013 DC Kids ads.
She is seen in her own catalogue modelling a colourful range of swimwear options for babies.
Her proud mum, Miami TV host Cecilia Elizalde said that her daughter 'teaches us much more than we will ever teach her'.
And in a statement about its decision to choose Valentine, Cortes said: "People with Down syndrome are just as beautiful and deserve the same opportunities.
"I'm thrilled to have Valentina modelling for us."
She is not the first model to be born with Down's Syndrome who has featured in a brand's ad campaign.
See Natty's lovely pics below: