Federal Disability Retirement: Can Federal Employees Appeal an OPM denial of disability retirement?

The short answer to that question is “generally, yes”.

Disability retirement is available to Federal Employees who become disabled in the course of their employment. The disability need not have occurred while at work.  Whether or not an employee is eligible for  disability retirement depends on which Retirement System the employee works under.

CSRS employees must be employed for a minimum of 5 years and be no longer able to effetcively perform at their current grade or pay level due to a [...]