Two sailors were treated for minor burns after the USS Chancellorsville was struck by the unmanned aircraft during radar testing Saturday afternoon, off Point Mugu in Southern California.
Lt. Lenaya Rotklein of the U.S. Third Fleet said the drone - which was 13 feet long, 1 foot in diameter and had a wingspan of nearly 6 feet - hit the ship's left, or port, side.
She said investigators at Naval Base San Diego are assessing the damage and determining why the drone malfunctioned.
About 300 crew members were aboard the ship. The Navy could not say how the two sailors were injured.
Rotklein identified the aerial drone as a BQM-74 series, manufactured by Aerospace giant Northrop Grumman Corp. She said the Navy makes frequent use of the unmanned aircraft in testing for combat and weapons systems. According to the company website, the drones can simulate enemy missiles or airplanes.