Risk Classification: Class I, II and III in Mexico

1. Key takeaways

Mexico classifies medical devices into three classes by use risk: Class I, Class II and Class III. The criteria are set out in RIS Articles 83 and 83 Bis: Class I covers devices that are well known in medical practice, whose safety and effectiveness have been demonstrated, and which do not ordinarily enter the body; Class II covers devices that are known but may vary in materials or concentration, that ordinarily enter the body and remain there for less than 30 days; Class III covers devices that are new or recently accepted, or that enter the body and remain for more than 30 days. Because the boundaries are stated in the regulation itself, the classification analysis is a legal exercise as much as a technical one: the wording of the intended use, the dwell time of the device in the body, and the novelty of the technology all feed directly into the class. A classification that is not supported by this statutory reasoning will not survive review, so companies should build the analysis from the article text outward rather than from the product spec inward.

2. Legal basis

Four instruments shape the classification outcome: the regulation sets the classes, the pharmacopeial supplement provides the detailed rules, the 2025 low-risk agreement overlays a separate low-risk track, and the Federal Duties Law links the class to the official fee. The table below summarizes each source.

The four sources operate in a fixed sequence in practice. The regulation answers the primary question of which class the device belongs to. The supplement rules then refine that answer for specific product situations where the general statements leave room for interpretation. The agreement is consulted afterwards, because it changes only the registration obligation for listed low-risk products and not the class itself. The fee provision comes last, converting the confirmed class into the applicable charge. Following this order keeps the analysis honest: the class is never chosen to obtain a fee level, and the low-risk track is never used as a substitute for a class determination that was never made.

3. Expert insights

Insight 1: The 30-day threshold is a hard boundary. For a single product, simply stating in the intended use that the device enters the body and remains for more than 30 days moves it from Class II to Class III. This number directly determines review intensity, dossier depth and official fees, and it is the single most common error point in classification arguments. Since the threshold is expressed in the regulation, the claim about dwell time must be defensible: it should be consistent with the clinical use pattern, the labeling and the instructions for use. Where a device is used in ways that vary in duration, the classification should address the longest intended dwell time, because an under-declared duration discovered later forces a reclassification exercise that touches the dossier, the fees and the approval itself.

Insight 2: A class is not the same as low risk. The 2025 agreement establishes a separate low-risk track that is not identical to Class I. A group of Class I devices is listed in Annex II and exempted from registration, while other products have been moved from exemption back to Annex I where registration is again required. The two frameworks must be assessed separately: a product can be Class I and still require registration under Annex I, and low-risk status under the agreement never overrides the class system for devices outside the annexes. Companies that treat Class I as a synonym for exemption expose themselves to import refusals and enforcement questions at the border.

Insight 3: A classification error is not automatically downgraded or corrected. In practice, COFEPRIS typically handles applications with a mismatched classification by refusing admission or by requesting correction, rather than reassigning the class on the applicant’s behalf. The classification argument therefore belongs before dossier preparation, not inside it as a figure-out-later exercise. Building the class determination as a standalone, citable document lets the rest of the dossier be scoped correctly the first time and avoids the compounding cost of preparing evidence for the wrong depth of review.

Insight 4: The class connects directly to money. Article 195-A of the Federal Duties Law sets fees by class, the amounts for the three classes in 2026 differ, and renewals and amendments are calculated as proportions of the registration fee. A classification error therefore propagates through the whole budget lifecycle: the initial filing, every subsequent variation and the eventual renewal are all priced off the class. Getting the class right is one of the cheapest risk controls available in a Mexican registration project.

4. Practical recommendations

1. Write the classification rationale as a standalone document that works through RIS Articles 83 and 83 Bis rule by rule and then through the 23 rules of the FEUM supplement, noting which specific rule is applied at each step.
2. Make explicit declarations on dwell time, entry into the body and sterility status, and align the label and the instructions for use with those declarations so no document contradicts another.
3. Review the low-risk track separately: check Annex I (registration required) and Annex II (registration exempt) directly, and never presume exemption from Class I status alone.
4. For product families, classify according to the most stringent model in the family to avoid later reclassification when variants are added.

5. Verification checklist

• □ Class determined under RIS Articles 83 and 83 Bis
• □ Checked against the 23 rules of the FEUM supplement
• □ Confirmed whether dwell time exceeds 30 days
• □ Checked placement under Annexes I and II of the 2025 agreement
• □ Classification conclusion consistent with the applicable fee tier

Regulatory information verified as of October 28, 2026.

How GRZAN can help. GRZAN provides medical device and IVD registration, quality system, authorised representative and local testing support for the Mexican market. Our team manages COFEPRIS registrations and equivalence (equivalencia) reviews, coordinates third-party authorised centre routes, and supports post-market vigilance obligations. Business enquiries: info@grzanglobal.com