The Constitutional Court ruled Thursday that the current law requiring large grocery stores to close at least two days a month is not against the nation's highest law.
The Distribution Industry Development Act allows mayors and other local government heads to restrict business hours of superstores in order to prevent such big businesses from dominating the market and to guarantee rest for store workers.
Under the law, superstores in Seoul have to close on the second and fourth Sundays of every month.
"The legislative purpose (of the law) is to prevent the distortion of order in the retail market by monopolization by a handful of large retail businesses with strong capital powers and to establish a healthy order in the retail market," the court said.
The court said the law specified public interests stipulated in the Constitution.
It also rejected claims that restriction of business hours at large stores is not effective in increasing sales at traditional markets, saying there is no such data backing up the claim.