I have received numerous telephone calls which indicate that there are many people who are confused, misinformed, or ill-informed about the issue of Social Security disability, filing for it, when to file for it, etc., in conjunction with filing for Federal Disability Retirement benefits under FERS (obviously, if you are under CSRS, you do not need to file for it). For informational purposes, here is the bottom line: Whether or not you plan to actually qualify for Social Security disability benefits, the only concern with respect to meeting the requirement for the Office of Personnel Management, as part of the FERS disability retirement application, is as follows: OPM really doesn’t care when you file, so long as you have filed and show a receipt on or before the day they approve your disability retirement application.
Thus, many people will tell me that they were “informed” by their Human Resources personnel that they must file with Social Security first before they can file for OPM disability retirement under FERS (not true); or, that they must have a decision by Social Security before they can file under FERS (even more untrue); or, that OPM will not even look at a federal disability retirement application unless you have first filed with Social Security (again, untrue). The bottom line: Yes, you must file for Social Security, but OPM doesn’t need to see a receipt showing that you filed, until the day they approve your OPM disability retirement application. So, sometime before the Federal Disability Retirement application gets to OPM, or, in those cases where one has procrastinated for too long, even after the application gets to OPM, you need to file for Social Security disability benefits, and have a receipt ready to show OPM.
Sincerely,
Robert R. McGill, Esquire
OPM Disability Retirement, Et Cetera… 
What if you are on CSRS Offset? Do you have a requirement to file for SS disability?
Yes, Karan, If you are CSRS offset, you must file for SS Disability. I don’t understand the problem with doing so. I went online with SSA and got all the forms, etc and set up an appointment. As part of my application, I turned in a COMPLETE copy of all the paperwork (medical files, reports etc) with the application (over 500 pages for my case). The case worker was a bit startled at first, but said this would speed up the process. I was collecting SS benefits for two months before I started getting OPM benefits. I then returned to OWCP and still receive SS benefits (though a lesser rate). This week I received notification that I am also eligible for Medicare. (I am 60)