It happened about 6:30 p.m. just east of the Highway 76 bridge near Forsyth, Missouri.
The Highway Patrol says Water Patrol officers responded along with the Taney County Sheriff's office to a report of a drowning.
Witnesses on scene told the patrol the man was swimming in the lake when he began struggling.
The man was pronounced dead at the scene.
His name is not being released until his next of kin is notified.
And two accidents involving boats at Lake of the Ozarks injures two people, one of them seriously. The Water Patrol says Eric Ackerman of Dayton, Ohio was seriously hurt Wednesday morning when his runabout boat hit a large wake, sending him airborne. The mishap happened at the 23 mile mark of the lake.
And a similar accident happened a couple of hours later not far from the first. The Water Patrol says Craig Gresham, 44, of Laurie, Missouri early Wednesday afternoon at the 24 mile mark of the lake, when his jet ski jumped a boat wake. Gresham broke his leg on the side of the boat.