RE: past tax returns - do you mail them together or separately?

[mlj616]

When mailing in late/past tax returns to the IRS for multiple years, do you mail them all in the same envelope? or do you have to mail them separately by year? Does it matter? 

[rjs · Accepted solution]

Yes, it matters. Mail each tax return in a separate envelope.

If you put more than one return in the same envelope, there is a very high probability that only one of them will be processed.