The incident happened at approximately 10:55 a.m. on the 12000 block of Central Avenue. Authorities said the suspect entered the bank and demanded cash from the teller.
He told the teller he was armed, but he did not display a weapon. The suspect left the bank with an undisclosed amount of cash.
He was described as a white male, between 30 and 40 years old, about 6 feet tall, and wearing a brown T-shirt and blue denim shorts.
Anyone with information was asked to call Chino police at (909) 628-1234.