Do sweepstakes ask for a Social Security number? Generally, legitimate sweepstakes do not require participants to provide their Social Security number, as this information is not necessary for entry. However, some contests may request it for tax purposes if you win a significant prize. It's essential to be cautious and verify the legitimacy of the sweepstakes before sharing any personal information. Always remember, do sweepstakes ask for a Social Security number? If they do, consider it a red flag and proceed with caution.