Sixty-four-year-old Patricia Roscher opted to take her winnings in a one-off lump-sum payment of $1.25 million.
Roscher, who works as a financial analyst for a credit card company, said she plans to take an early retirement and buy a new home to share with her long-time partner.
Lottery officials say Roscher is the 401st person to win a Missouri Lottery prize of $1 million or more.
Missouri Lotto draws are held on Wednesdays and Saturdays. The estimated jackpot for Wednesday, May 5, is $1.6 million.