According to new research, 51% of US mobile ad impressions came via Google's Android platform in February, almost double the number gained by Apple.
As revealed by Brand Republic, the stats represent a remarkable turn around for Android devices, which accounted for just 6% of ad impressions in March last year.
The report, compiled by Millennial Media shows Apple devices commanding 27% of ad impressions, while Blackberry had 17%.
This time last year, Apple accounted for 70% of mobile ad impressions in the US.
The research also found that connected devices, such as tablets like the Apple iPad were on the rise, fueling an increase in ads by 56% from 2010.
Millennial Media predicted that by 50 million iPads will be in operation by 2012, but that Apple will face a challenge from Android tablets, which the firm expects to sell 32 million units of by the end of 2012.