Negotiators from the Hoover Dam Police and Las Vegas Metro Police tried for 2 hours to persuade the man not to jump from the Mike O'Callaghan-Pat Tillman Memorial Bridge, the Las Vegas Sun reported.
The man, who was not identified by the Sun, jumped from the Nevada side of the bridge at 12:30 p.m. and hit rocks before reaching the river, officials said.
His body was recovered from the water.
The man became the third person to commit suicide by jumping off the bridge, which opened in October 2010, the Sun said.
The 1,900-foot-long bypass bridge spans the Black Canyon, downstream of the Hoover Dam, and is the country's second-highest bridge.