Central Reexamination Unit (CRU) of the USPTO

The Central Reexamination Unit (CRU) is a specialized administrative unit within the United States Patent and Trademark Office (USPTO), not a federal district court. Based in Alexandria, Virginia, the CRU is responsible for overseeing the examination and handling of post-grant patent proceedings, including ex parte reexaminations, supplemental examinations, and reissue applications for all technologies except designs. It centralizes these functions to ensure consistent and high-quality examination. Recent trends indicate a significant increase in reexamination requests, with filings doubling from the first half of 2023 to the first half of 2024, and sometimes surpassing America Invents Act (AIA) petitions at the Patent Trial and Appeal Board (PTAB).

The CRU's "patent docket reputation" is focused on its role in assessing patent validity based on prior art. The unit aims for objective and timely processing, adhering to a "special dispatch" mandate. Reexamination proceedings are typically limited to considering patentability issues based solely on prior art patents and printed publications. Historically, reexaminations often result in patents having their scope narrowed, with recent statistics showing that 64% of challenged claims are either canceled or narrowed. While the CRU operates independently, federal court decisions are considered, and final non-appealable judgments of invalidity are controlling. District courts have also shown an increased willingness to grant stays in litigation pending CRU reexaminations in 2024 and 2025.

Procedures for patent reexamination before the CRU are outlined in the Manual of Patent Examining Procedure (MPEP), particularly Chapter 2200. A request for reexamination must establish a "substantial new question of patentability" (SNQ) based on prior art. The USPTO is statutorily required to determine whether an SNQ exists within three months of the request filing. In ex parte reexamination, proceedings are generally limited to two office actions. Patent owners also bear the duty to promptly notify the USPTO of any related federal court decisions.

Among the tracked cases, Unified Patents v. Competitive Access Systems involved an ex parte reexamination of U.S. Patent 10,868,908. Unified Patents filed the request on October 4, 2023, which the CRU granted on January 2, 2024, finding substantial new questions of patentability. Subsequently, on October 2, 2024, the CRU issued a final rejection for all challenged claims. Similarly, in Unified Patents LLC v. Monticello Enterprises LLC, Unified Patents filed an ex parte reexamination request against U.S. Patent 11,468,497 on April 26, 2024. The CRU granted this request on June 14, 2024, and issued a final rejection of all challenged claims on November 7, 2024.

The CRU is staffed by experienced professionals, including senior primary patent examiners and supervisory patent examiners, often referred to as "Patent Reexamination Specialists." These individuals are specially selected, possessing extensive examining experience (averaging 15-20 years) and often advanced technical and law degrees. A key policy is that reexamination requests are assigned to an examiner different from those who were involved in the original examination of the patent. As of a March 2026 USPTO Hour, key personnel included Fenn C. Mathew as the Acting Director and Stephen J. Stein as a Management Quality Assurance Specialist for the CRU.