The latest theft occured Sunday night. Security at the race track say it's difficult to monitor the entire grounds of the track 24 hours a day.
Barns at the Red Mile are accessible nearly all the time during the live racing season allowing people who take care of the horses to come and go.
The theives are thought to strike between 9pm and 4am. So far security is yet to catch them but have been told two suspcious men have been seen on a couple occasions around the barns in question.
The criminals are taking the copper piping that connects the water heaters of each barn.
Security officials say it's not the amount of copper that's being stolen, around $200 to $300 worth, but rather the amount of money it will take to replace the damage.
Anyone with information is asked to call the Lexington Police.