"I didn't," Lee responded when a reporter asked if he bribed officials, Yonhap reported.
Lee then blamed the media "who have passed on such things."
Prosecutors have already questioned Lee's wife Hong Ra-hee and several other family members, Yonhap reported.
The investigation began after Kim Yong-chul, a former Samsung attorney, alleged in January the company had set up a $202 million fund for bribing officials.
The scandal has South Koreans on edge. The company accounts for nearly a quarter of the nation's exports and gross national product, the report said.