Note about free Social Security Death Index Access: In late 2011, a number of genealogy sites , the public version of the SSA Death Master File. The following sites still provide free SSDI access as of December 2015:
Free online search of the SSDI, a name index to deaths recorded by the Social Security Administration beginning in 1962. Free, unrestricted search. This database was last updated on 28 February 2014, just prior to restrictions enacted in March 2014 which require that newly reported deaths will not be made available in the public version of the Social Security Death Index for three years after the individual’s death.

As such, new deaths reported after February 2014 will not be available in this database until 2017.

Mocavo offers a free search of the Social Security Death Master File, current through 2010, containing approximately 88 million records. Results do include social security numbers.
Tom Alciere makes available this free version of the Social Security Death Master File, current as of November 2011, and searchable by name or social security number. This copy does not have available the death residence location or death benefit payout ZIP Code. For additional search features for accessing these files, check out the at DonsList.net.
Advanced search features make this free version of the SSDI easy to use (with registration). However, it is only current through 2011, stating that due to compliance with Section 203 (“Restriction on Access to the Death Master File”) of the Budget Act of 2013, they are “no longer able to display SSDI records for individuals who have died within the previous 3 years.” More importantly, GenealogyBank does not provide social security numbers for any individual in the database, whether or not the death was recent.
Steve Morse has created a very handy search form which enhances the search abilities of many of the free SSDI search engines on the Web. You can choose from a variety of free SSDI databases to search through this flexible search interface.
Ancestry.com also offers a , but it is available only to paying subscribers and not free. It is current through mid-March 2014, but does not include social security numbers for individuals who died within the past 10 years. Going forward, new records will be available when they are older than 3 years (1095 days), to comply with U.S. law.