ERAS is the application system for both residency and most (all?) fellowships. To use ERAS for fellowships, you need to get a token from their website: Token Registration - ERAS® Fellowships Documents OfficeHi
Do I use the same NRMP I used for residency for fellowship application or do I create a new one?
Two things.EDIT: Sorry, I misread your post. I don't know if you use the same ERAS login, somehow I'd doubt it as there is a focus on different stuff and much of your CV will be different.
1. ERAS is the application service, not the matching service. NRMP is the matching service. Some fellowships use ERAS, some do not.
2. Your login for ERAS is the same as for residency, but you have to fill out a completely new application. This is because your ERAS login is linked to your AAMC number, which you used for applying to medical school as well. All your demographics have already been verified that way.
OP, I haven't registered for NRMP for fellowship, because it doesn't open till the end of September for my match (all matches this year?), but I imagine they will have some information on file for you, and you just specify which match you are participating in.