An investigation by the state attorney general's office at five Wal-Mart stores found as much as 80 percent of the merchandise didn't carry price tags.
While an Okemos store near Lansing had price tags on 75 percent of its merchandise, only 25 percent of the items in a Saginaw store had tags.
Stores in Roseville, Coldwater and Howell stores had price tags on 20 percent of their merchandise.
In four of the grocery stores, only 1 percent to 10 percent of items had price tags.
Attorney General Mike Cox said today that he's taking legal action against Wal-Mart. The company has ten days to comply with the law and could face fines.
A company spokeswoman says Wal-Mart sometimes changes prices on more than five-thousand items a week, making it difficult to comply.
Wal-Mart has 40 supercenters and 37 discount stores in Michigan.