"As a leader, these are some of the toughest decisions to make," he wrote. "While difficult, I believe changes will help us become a more nimble organization that serves customers better."
Shares of Wal-Mart were down more than 1 percent after the news.
The cuts at the Arkansas offices are part of a reorganization of the retailer's management structure, the memo said. Due to "changing customers and retail" the CEO said "we must change."
"We are grateful for their service," McMillon wrote. " Taking care of therm is a priority, and we are providing these associates access to services and resources that will help them find their next opportunity."