Macho Man Randy Savage -- one of the greatest wrestlers of all-time -- died today in a car accident in Tampa, Florida ... TMZ has learned.

TMZ spoke with Randy's brother, Lanny Poffo, who tells us the wrestling legend suffered a heart attack while he was behind the wheel around 10 AM ... and lost control of his vehicle.

Earlier this month, Savage celebrated his 1-year anniversary with his new wife Lynn.

Savage was 58.

Macho Man began wrestling in the WWF in 1985 and became a superstar with his trademark catchphrase "Ooooooh Yeaahhhhh."

UPDATE: Florida Highway Patrol tells TMZ ... Savage was driving his 2009 Jeep Wrangler on a when he veered across a concrete median ... through oncoming traffic ... and "collided head-on with a tree."

Savage was transported to Largo Medical center, where he died from his injuries.