Can a patent application be returned to the applicant after filing?

No, patent applications that are entitled to a filing date will not be returned to the applicant, even if requested. This applies to applications filed by regular mail, Priority Mail Express, hand-delivery, or through the USPTO patent electronic filing system.

The MPEP clearly states: ‘Applications which are entitled to a filing date, whether filed by regular mail, by Priority Mail Express® under 37 CFR 1.10, by hand-delivery, by the USPTO patent electronic filing system, or otherwise, will not be returned to applicant even if requested.’ (MPEP 503)

Applicants should be careful not to file duplicate applications or applications not intended for filing, as fees paid for such applications are generally not refundable due to a change of purpose.