If any member of the public becomes aware of a pending application which he or she believes should not gain patent status, that individual has the right to file a protest in reference to the application. A protestor must have a good reason as to why the pending application should not be allowed. Valid protest reasons include; information concerning the patentability of the subject matter (i.e., if it was on sale or published more than a year before the filing of the application) or if the inventorship is inaccurate.

The basics of protests should be understood. It is important to know the differences between protests, reexaminations, reissues, interferences and appeals. The PTO will try to incorporate these topics into questions in a confusing manner, so be sure to understand the differences.

1901 Protest under 37 C.F.R. 1.291

§ 1.291 Protests by the public against pending applications.
(a) A protest may be filed by a member of the public against a pending application, and it will be matched with the application file if it adequately identifies the patent application. A protest submitted within the time frame of paragraph (b) of this section, which is not matched in a timely manner to permit review by the examiner during prosecution, due to inadequate identification, may not be entered and may be returned to the protestor where practical, or, if return is not practical,
discarded.
(b) The protest will be entered into the record of the application if, in addition to complying with paragraph (c) of this section, the protest has been served upon the applicant in accordance with § 1.248, or filed with the Office in duplicate in the event service is not possible; and, except for paragraph (b)(1) of this section, the protest was filed prior to the date the application was published under § 1.211, or a notice of allowance under § 1.311 was mailed, whichever occurs first:
(1) If a protest is accompanied by the written consent of the applicant, the protest will be
considered if the protest is matched with the application in time to permit review during
prosecution.
(2) A statement must accompany a protest that it is the first protest submitted in the application by the real party in interest who is submitting the protest; or the protest must comply with paragraph (c)(5) of this section. This section does not apply to the first protest filed in an application.
(c) In addition to compliance with paragraphs (a) and (b) of this section, a protest must include.
(1) A listing of the patents, publication, or other information relied upon;
(2) A concise explanation of the relevance of each item listed pursuant to paragraph (c)(1) of this section;
(3) A copy of each listed patent, publication, or other item of information in written form, or at least the pertinent portions thereof;
(4) An English language translation of all the necessary and pertinent parts of any non-English language patent, publication, or other item of information relied upon; and
(5) If it is a second or subsequent protest by the same party in interest, an explanation as to why the issue(s) raised in the second or subsequent protest are significantly different than those raised earlier and why the significantly different issue(s) were not presented earlier, and a processing fee under § 1.17(i) must be submitted.
(d) A member of the public filing a protest in an application under this section will not receive any communication from the Office relating to the protest, other than the return of a self-addressed postcard which the member of the public may include with the protest in order to receive an acknowledgement by the Office that the protest has been received. The limited involvement of the member of the public filing a protest pursuant to this section ends with the filing of the protest, and no further submission on behalf of the protestor will be considered, unless the submission is made pursuant to paragraph (c)(5) of this section.
(e) Where a protest raising inequitable conduct issues satisfies the provisions of this section for entry, it will be entered into the application file, generally without comment on the inequitable conduct issues raised in it.
(f) In the absence of a request by the Office, an applicant has no duty to, and need not, reply to a protest.
(g) Protests that fail to comply with paragraphs (b) or (c) of this section may not be entered, and if not entered, will be returned to the protestor, or discarded, at the option of the Office.

What is a protest?:
a protest is a means for a third party to challenge whether a pending application should issue

Submitting a protest:
a. any member of the public or an attorney can file a protest without naming his or her client
b. the real party of interest does not need to be identified
c. the same party of interest may not file a subsequent protest unless they explain why the subsequent protest brings up issues that are significantly different from the earlier protests

Protest filings:
a. active participation by the protestor ends with the filing of the initial protest and no further submission on behalf of the protestor will be acknowledged or considered unless the submission is made pursuant to 37 CFR 1.291(c)(5).

When to submit a protest:
a. protests may be filed throughout the pending of a reissue application prior to the date of mailing the Notice of Allowance
b. protests for reissue applications should be filed within the 2-month period following their announcement in the Official Gazette if possible
c. where a final rejection has been issued or the prosecution on the merits has been otherwise closed for a reissue application, a petition under 37 CFR 1.182 along with the required fee for entry of the protest are required

Compliance
a. a protest that is submitted in compliance with 37 CFR 1.291(a), (b) and (c) will be considered by the Office if the protest is matched with the application in time to permit review by the examiner during prosecution
b. the receipt of the self-addressed postcard from the Office is not an indication that the protest complies with 37 CFR 1.291
i. the postcard receipt only shows that the Office has received the protest
c. improper protests will be returned to the protestor or discarded at the option of the Office

effective November 22, 2004, 37 CFR 1.291(c) was amended to no longer permit the submission of additional (cumulative) prior art by the same real party in interest