The sweat-stained cap from around the 1920s sold at an auction of Yankees memorabilia in New York.
Hunt Auctions says the cap is one of only three Yankees hats in existence worn by Ruth during games. It says a hat used by a player had never sold for more than $100,000.
The Ruth cap had been expected to fetch up to $200,000. The surname Ruth and the player's first and middle initials, G.H., for George Herman, are embroidered inside.
A Ruth bat signed to Broadway star Tessa Kosta sold for $195,500. And Thurman Munson's 1970 Rookie of the Year award sold for $46,000.
The auction continues Tuesday with a jacket Lou Gehrig wore the day he ended his streak of 2,130 consecutive games played.