ComScore's survey of 30,000 users found that Android's market share grew by 15% compared to its February survey results. That survey found that 33% of all smartphone subscribers used Android.
The popularity of Apple's iPhone also grew in the latest survey, as its U.S. market share increased from 25.2% share in February to 26.6% share in May, a 5% hike, ComScore said.
The shares of all the other major platforms declined over the period.
For instance, Research in Motion's share of the smartphone market dropped to 24.7% share from 28.9% in the earlier report. The decline let Apple take over second place in the survey.
Microsoft's held 5.8% of the market in the latest survey, down from 7.7% in the February report. Palm's share declined from 2.8% to 2.4%, ComScore said.
The ComScore results are strikingly similar to last week's Nielsen U.S. report that covered roughly the same period.
The Nielsen survey found that Android had a 38% share smartphone market share in its May report, up two percentage points from three months earlier.
to 27% from 26%, Nielsen said.
Nielsen blogged that the iPhone had shown the most growth in recent months, although ComScore's data indicates otherwise.
Both surveys are considered highly reliable.
Nielsen surveys between 20,000 to 25,000 mobile subscribers each month, compared to about 30,000 in the latest ComScore results.
Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at , or subscribe to . His e-mail address is .
in Computerworld's Mobile and Wireless Topic Center.