Key Points: Manufacturing Readiness Levels (MRLs) originated in defense programs: they provide a structured, gate-based approach to manufacturing maturity that maps directly onto FDA process validation requirements. FDA 510(k) and PMA pathways each carry different manufacturing maturity expectations: understanding where your process must be at submission — not just at launch — prevents late-stage rework. Design History File (DHF) requirements align closely with MRL documentation: building MRL-style gate reviews into your development cadence produces the evidence FDA wants to see. IQ/OQ/PQ validation is manufacturing readiness by another name: treating process validation as a discrete event rather than a continuous development activity is one of the most common — and costly — mistakes in medical device manufacturing. DFM decisions made early determine whether scale-up is a formality or a crisis: tolerances, material selections, and process choices locked at prototype must survive production volumes, supplier variation, and regulatory scrutiny. What Are Manufacturing Readiness Levels in Medical Device Development? Manufacturing Readiness Levels (MRLs) are a structured, evidence-based framework for assessing whether a manufacturing process is mature enough to produce hardware reliably at scale. Developed by the U.S. Department of Defense, the MRL scale runs from 1 to 10 — MRL 1 represents an identified manufacturing concept, MRL 10 represents stable, full-rate production. Each level carries defined criteria: specific outputs, demonstrated capabilities, and documented evidence required before a program advances.