Police said the suspect said he had a weapon and asked for money. Police said he did not show a weapon. The teller gave him an undisclosed amount of money and he left.
Tishomingo County Sheriff Glenn Whitlock said nobody was hurt.
It had been a busy afternoon and customers were in the bank at the time. Authorities are on the lookout for a white male wearing a baseball cap, khaki shorts, white T-shirt and sneakers. He's about 6 feet tall with a medium to slight build.
The sheriff said he possibly left in a white or beige Ford Explorer. Nobody observed the direction of travel.
Anyone with information should call Iuka Police Department, (662) 423-6340, or Tishomingo County Sheriff's Department, (662) 423-7000.