Google's Android operating system appeared on 33 percent of all of the U.S. smartphones purchased in the second quarter, surpassing Research In Motion's BlackBerry devices and Apple's iPhone in units shipped.
NPD Group's latest research shows that RIM commanded 28 percent of the smartphones sold, with iPhone selling 22 percent for the quarter.
Sales of Android units, such as the Motorola Droid, HTC Droid Incredible and HTC Evo 4G, helped the OS overtake U.S. smartphone market leader BlackBerry OS, whose share dropped 9 points for the period.
RIM hopes to turn the tables on Android with smartphones such as the BlackBerry Torch 9800, based on the new BlackBerry 6 OS, this fall.
Apple's iPhone 4 is the more likely bet to best Android sales for the current third quarter.
Though the new device suffered from poor public relations after the attenuation issue that plagued users with dropped calls, Apple said it sold 1.7 million iPhone 4 units in the first weekend.
Now that the company is offering free bumper cases to mitigate the attenuation, it's likely iPhone 4 sales will accelerate.
"While the Google-developed OS took market share from RIM, Apple's iOS saw a small gain this quarter on the strength of the iPhone 4 launch," Ross Rubin, executive director of industry analysis for NPD, said in a statement Aug. 4.
Rubin isn't the only one to chart Android's success against BlackBerry and iOS.
NPD published his research two days after Nielsen said Android grew its subscriber base by 27 percent for the second quarter, while Apple only grew 23 percent.
However, Nielsen also noted that at 13 percent of total U.S. market share, Android still significantly lags BlackBerry (35 percent) and iPhone (28 percent).
Rubin also tracked U.S. consumer purchases of mobile phones in the second quarter and said the top 5 Android smartphones in sales were: Verizon's Motorola Droid, Verizon's HTC Droid Incredible, Sprint's HTC EVO 4G, Sprint's HTC Hero and Verizon's HTC Droid Eris.
The Motorola Droid X is also popular, selling out across the country since July 15. However, it isn't clear if NPD considered its sales in its study.
More broadly, he said Verizon Wireless sold 33 percent of the mobile phones sold in the United States in the second quarter, followed by AT&T with 25 percent, Sprint with 12 percent and T-Mobile with 11 percent.