First, a patent application is written, which is supposed to describe how to make and use the invention at a level adequate for one of ordinary skill working in that area. At the end of the patent application is a set of claims. Without going into the details of how to write a claim, the claims define the breadth of coverage that the applicant seeks for their invention (the best language for writing a claim and the manner in which the claims are interpreted is dictated by a fairly large body of case law).

After the application is written, it is filed with the Patent and Trademark Office. Within about three months, the Patent and Trademark Office sends a filing receipt, which includes a foreign filing license giving the Applicant permission to file the patent application in another country. However, despite the foreign filing license, it is possible that another government agency prohibits exporting the technology associated with the patent application to another country. Depending upon the art area into which the application is classified, about a year and a half after filing the application, an Office Action is sent by the US Patent and Trademark Office. However, sometimes the first Office Action received may be received as early as six months after filing the application, while at other times the first Office Action may not be received until four or five years after filing the application. How long it takes the US Patent and Trademark Office to send the first Office Action varies with the priorities set by the current presidential administration and according to the backlog of the individual unit and Examiner handling your application.

The first Office Action received may include a Notice of Allowance. More commonly, however, the first Office Action contains one or more rejections of some or all of the claims and/or one or more objections. Often, all of the claims will be rejected in the first Office Action. Since the objective of the claims is to obtain the broadest coverage to which the Applicant is entitled, a rejection in the first Office Action is not necessarily a bad thing, because the lack of a rejection in the first Office Action is some times an indication that the Applicant may be entitled to broader claims. The Applicant is typically given three months within which to reply to the Office Action. After three months, a reply may still be filed if a late fee is paid. However, ordinarily, a reply may not be filed more than six months after the mailing of the Office Action. In response to a rejection, the Applicant may amend the claims, the specification, and/or submit arguments as to why the rejections/objections of the Office Action should be withdrawn. However, although the wording of the specification may be amended, no new subject matter may be added to the specification that was not present in the originally filed application after the application is filed.

After filing the response to the Office Action, the US Patent and Trademark Office will usually reply within about three months with another Office Action. Again, this Office Action may contain a Notice of Allowance or may contain one or more rejections and/or one or more objections. The second Office Action is usually made final. This means that, although a response to the final Office Action may contain an amendment, the entry of the amendment is at the Examiner's discretion. After the Final Office Action, the Examiner will typically only enter amendments that place the application in condition for allowance without introducing any new issues that require further consideration. For example, an amendment that merely cancels rejected claims is likely to be entered, but an amendment that changes the wording in the claims in a manner that is not suggested by the Final Office Action is likely not to be entered.

The US Patent and Trademark Office usually replies to a response to a Final Office Action by sending an Advisory Office Action. The Advisory Office Action is typically very terse, and may only indicate the status of the claims and whether or not any amendments were entered. After the mailing of a Final Office Action, if the Examiner refuses to allow the patent application, a continuation or a request for continued examination (with the appropriate fee) may be filed. The filing of a continuation is a refiling of the original application, while retaining the benefits of the filing date of the original application. The filing of a request for continued examination is a filing of a request to continue to examine the application and send a new nonfinal Office Action in exchange for the payment of a fee. The Patent and Trademark Office uses the same set of fees to determine the filing fee for a continuation as for filing a new application. Filing a continuation or of a request for continued examination entitles the applicant to amend the application, and typically entitles the applicant to another two Office Actions (the second application being made final). In this respect filing a continuation or a request for continued application is almost like filing a new application.

After receiving a second Office Action, the Applicant may appeal the rejection to the Patent Trial and Appeals Board. If the Patent Trial and Appeals Board affirms the Examiner's rejection, the Applicant may in at least certain instances ask the Patent Trial and Appeals Board to reconsider their decision. Even if the Patent Trial and Appeals Board does not change its mind, the Applicant may, within a narrow period of time, still file a continuation with a new set of claims of a narrower or of a different scope, but not of a purely broader scope. More precisely, there is nothing stopping the Applicant from filing claims of the same scope or of a broader scope, but such claims will be rejected, and the rejection of these claims may be made final on the first Office Action because the Patent Trial and Appeals Board has already determined these claims to be unpatentable.

The decision of the Patent Trial and Appeals Board may be appealed to the Court of Appeals of the Federal Circuit (CAFC). After receiving a final decision from the Patent Trial and Appeals Board, the Applicant ordinarily has two months within which to file an appeal to the CAFC. A decision by the CAFC may be appealed to the Supreme Court. However, the Supreme Court does not accept many patent cases. Consequently, the CAFC is usually the highest court to which an application can be appealed. Further, only a relatively small percentage of applications filed are appealed to the CAFC. The above overview is not intended to give a complete description of all that may occur during the pendency of a patent application. The above is just an overview, there are many other possible nuances to the entire process.