The retailer is reportedly planning to launch a tailored US site, in September.
French and German sites will follow after the US launch.
Asos currently offers international shipping and last year 7% of its sales were from the US.
The US operation will initially trade out of the UK but it will eventually have its own warehouse and central operations.
There are also plans to find US brands and product ranges for the site.
Nick Robertson, the founder and CEO of Asos, told US title Women’s Wear Daily that he believes the US business will equal the UK business within 4 years.
Earlier this month, Asos.com announced plans to allow independent boutiques and designers to sell via the site.
Asos is also sponsoring the Global Radio 95.8 Capital FM Summertime Ball in a bid to bring the brand to life.