Social Security recipients have less than two months to switch to electronic payments.
Paper checks are being phased out in an effort to cut costs.
About 93% of payments are now made electronically but about five millions checks are still mailed each month.
The Treasury Department says that mailing costs 4.6 million dollars a month.
Those who fail to switch over will still get paper checks after March 1st.
A Treasury spokesman says they will contact those people in a quote "more personal, direct way" to ask them to switch.
To sign up for benefits, recipients can visit www.GoDirect.org , call a toll-free helpline at 1-800-333-1795 or speak with their local bank or credit union representative.