35 U.S.C. 112, Specification

Executive summary:

Potential for Errors: This document contains one section of the U.S. Patent Act (found in Title 35 of the United States Code) as amended by the Leahy-Smith America Invents Act. This page was last updated in November 2011. While the page has been edited to help ensure that the changes made by the AIA to this section are reflected in this document, errors are possible. If you notice such errors, please contact Dan Tysver at (

Alternate Views: This page uses stylesheets to allow different views of this statutory section. By clicking on the buttons below, one can view this section in a redline version reflecting the changes made by the AIA, a clean version showing the section after the AIA, or an original version showing the original section before the AIA. There is an index page and an all-sections page for this version of 35 USC.

Effective Date: Various sections of the AIA are implemented using different effective dates. If changes have been made to this section of the Patent Act, the effective date(s) for those changes are found in the implementing section of the AIA, and are reproduced below for your convenience.


Redline Clean Version (after America Invents Act) Original (before AIA)


Previous Section (§111) | Next Section (§113)

35 U.S.C. 112 Specification.

(a) IN GENERAL.--The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention of carrying out his invention.

(b) CONCLUSION.--The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention applicant regards as his invention.

(c) FORM.--A claim may be written in independent or, if the nature of the case admits, in dependent or multiple dependent form.

(d) REFERENCE IN DEPENDENT FORMS.--Subject to subsection (e), Subject to the following paragraph, a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.

(e) REFERENCE IN MULTIPLE DEPENDENT FORM.--A claim in multiple dependent form shall contain a reference, in the alternative only, to more than one claim previously set forth and then specify a further limitation of the subject matter claimed. A multiple dependent claim shall not serve as a basis for any other multiple dependent claim. A multiple dependent claim shall be construed to incorporate by reference all the limitations of the particular claim in relation to which it is being considered.

(f) ELEMENT IN CLAIM FOR A COMBINATION.--An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.

(Amended July 24, 1965, Public Law 89-83, sec. 9, 79 Stat. 261; Nov. 14, 1975, Public Law 94-131, sec. 7, 89 Stat. 691.)

Effective Dates for Changes Made to this Section

Section 4 of the America Invents Act

(e) EFFECTIVE DATE.--The amendments made by this section shall take effect upon the expiration of the 1–year period beginning on the date of the enactment of this Act and shall apply to any patent application that is filed on or after that effective date.