Can I apply for both early retirement benefits and SSDI?

You can apply for both programs but you will not receive payments from both. If you apply for early retirement you will receive retirement benefit payments at a reduced amount. If you are then awarded SSDI, the most significant change you will see is a slight increase in your monthly benefits. Any retroactive SSDI benefits payable will also be offset during any months that you received early retirement benefits. In other words, your retroactive benefits for any month you received early retirement will equal the difference between those benefits and your SSDI benefit amount.

Most of this information comes directly from SSA and can be found on their website.