The warehouse-store chain said the dresses will only be available at its stores for a limited time and will then be available for purchase online, KING-TV, Seattle, reported Monday.
The store said it is stocking six styles of dresses for $700 to $1,400.
Costco shopper Mary Haltiner said the plan could prove successful for the company.
"I doubt they'd put it next to the hamburgers but they sell coffins online so why not wedding dresses?" she said.