The milestone was reached Wednesday just before 5 p.m. EDT when Brandon Ashmore of Mentor, Ohio, downloaded the Say the Same Thing app by Space Inch, Apple confirmed Thursday morning.
The 50 billion figure was for unique downloads, not counting re-downloads and app updates, CNET reported.
Users have been downloading more than 800 apps per second at a rate of over 2 billion apps per month on the App Store, which opened in July 2008 with a mere 500 apps.
App Store customers went from the previous milestone of 25 billion app download to 50 billion in just 14 months, Apple said.
Apple remains slightly ahead of competitor Google, which announced Wednesday downloads from its Google Play store stood at 48 billion app installations.
Apple's App Store offers more than 850,000 apps to iPhone, iPad, and iPod Touch users.