Summary: Section 610 of the Regulatory Flexibility Act of 1980 requires federal agencies to develop a plan for the review of their existing rules that will have a "significant economic impact on a substantial number of small entities." The purpose of these reviews is to decide whether the rules should continue unchanged or should be amended or rescinded to minimize their impact on small entities, which include small businesses and small governmental jurisdictions. Agencies are required to provide an annual Federal Register notice of rules they intend to review in the next 12 months. Several agencies have used the Unified Agenda of Federal Regulatory and Deregulatory Actions to publish these notices. This report updates GAO's earlier work on this issue. GAO determines, with regard to the April 1998 and November 1998 editions of the Unified Agenda, (1) how many agencies had no Agenda entries that were characterized as section 610 reviews, whether agencies are interpreting the review requirements consistently, and why some agencies that appeared subject to the requirements had no entries; (2) how many of the section 610 review entries in the Agenda appeared to meet the notification requirements in subsection 610(c); (3) if the section 610 review entries did not appear to meet the statutory requirements, why some agencies' entries were not characterized as section 610 review; and (4) whether any federal agencies had revised their plans for section 610 reviews.