ICD codes in the United States are updated twice a year, with major changes taking effect on October 1 and a second round of updates on April 1. This twice-yearly cycle has been in place since 2022, replacing what was previously a once-a-year update every October. Internationally, the World Health Organization follows a different schedule, publishing minor updates annually and major revisions every three years.
The U.S. Update Cycle: October and April
The primary update to ICD-10 codes happens every October 1, aligned with the federal government’s fiscal year (which runs from October 1 through September 30). This is the annual release that adds new codes, retires old ones, and revises descriptions. It’s been the cornerstone of the update process for years.
Starting in April 2022, a second update window was added on April 1 of each year. This mid-year release gives the system more flexibility to respond to new diseases, technologies, and clinical needs without waiting a full year. The April 1 update replaces the October 1 file for the remainder of that fiscal year. So if you’re looking at the current FY 2026 cycle, one set of codes covers October 1, 2025 through March 31, 2026, and the updated set covers April 1, 2026 through September 30, 2026.
This pattern is consistent. Looking at recent years, April updates were published in 2022, 2023, 2024, 2025, and 2026. The April 2020 release was a special case, adding COVID-19 codes and guidelines before the formal twice-yearly system existed.
Who Manages the Updates
Two different federal agencies handle the two main ICD-10 code sets. The CDC’s National Center for Health Statistics maintains ICD-10-CM, the diagnosis codes used by every healthcare provider in every setting. CMS (the Centers for Medicare and Medicaid Services) maintains ICD-10-PCS, the procedure codes used specifically for inpatient hospital procedures. Both code sets follow the same October 1 and April 1 update schedule.
Proposed changes go through the ICD-10 Coordination and Maintenance Committee, which holds public meetings twice a year, in spring and fall. Anyone can submit a request for a new or revised code, and these requests are discussed openly at the meetings. However, no final decisions are made during the meetings themselves. Final approval goes through a clearance process within the Department of Health and Human Services.
How Code Proposals Become Official
If you or your organization submits a code request, you’ll need to specify whether it’s intended for the April 1 or October 1 implementation date. Proposals discussed at the spring meeting are typically aimed at the following October 1 implementation, while those at the fall meeting may target the next April 1 date. The timeline from proposal to live code spans several months, since the committee needs time for public discussion, review, and final clearance.
The ICD-11 Update Model
The World Health Organization, which publishes the international version of ICD, uses a rolling maintenance approach for ICD-11. Minor updates are published annually, and major updates come out every three years. ICD-11 also has an internet-based proposal platform where clinicians and researchers worldwide can suggest changes year-round. Those contributions are reviewed for possible inclusion on an annual basis.
The U.S. has not yet transitioned to ICD-11. American providers still use ICD-10-CM and ICD-10-PCS, so the domestic October/April update cycle is what matters for billing and reporting in the U.S. today.
When Updates Were Paused
There’s one notable exception to the regular update rhythm. During the transition from ICD-9 to ICD-10, the government implemented a “partial code freeze” to give the healthcare industry time to prepare. The last full annual updates to both ICD-9 and ICD-10 were made on October 1, 2011. From October 2012 through October 2015, only limited changes were allowed, restricted to new technologies and diseases required by law. ICD-10 officially went live on October 1, 2015, and regular, unrestricted updates resumed on October 1, 2016.
This freeze lasted about five years in total and created a backlog of needed code changes. It’s unlikely to happen again unless another major system transition occurs.
What This Means in Practice
If you work in medical coding or billing, you need to check for updates twice a year. The October 1 release is typically the larger of the two, but the April 1 release can include meaningful additions and revisions. Using outdated codes after either effective date can result in claim denials.
CMS publishes the updated code files, guidelines, and addenda on its website well before each effective date. The CDC also posts ICD-10-CM files with clear labels showing which date range each release covers. Keeping track of both windows, not just the October cycle, is now a standard part of staying current.