It happened at Rockville Bank in South Windsor Thursday afternoon.
Kendl Murphy, 43, pulled up to the drive-up teller and handed over a deposit envelope that contained a small bag with white powder. Bank staff asked Murphy to wait for her transaction to be completed and called police.
A field test of the substance revealed that it was cocaine.
Murphy has been charged with possession and possession within 1,500 feet of a school or day care. She was later released on a $1,000 bond.