The business, which sells more than 65,000 branded and own-label products to fashion-conscious men and women in their twenties, said its total active users were up 41% to 7.9 million.
Chief executive Nick Robertson said: "Retail sales in the UK were particularly strong at [an increase of] 37%, and international sales grew by 38%.
"These results were driven by significant improvements to our customer proposition, including better delivery options, additional payment methods and the rollout of our premier service in key international markets."
He added that work on significantly increasing the company's Barnsley site continues as it plans to open its central European distribution centre later this year.
At the start of December last year, Asos had already beaten Amazon and John Lewis to top spot for the most-shared content on Pinterest in the lead-up to Christmas, leaving Debenhams and Marks and Spencer trailing.
Prior to this, Robertson had completely ruled out opening a physical store to compement its online business, describing the notion as "counterintuitive".