An ISO 9001 nonconformance is a failure to meet a stated requirement within a quality management system. In manufacturing, it may involve a product characteristic, process step, procedure, record, supplier activity, or system control that does not conform to defined requirements.
The term is commonly used during audits, inspections, production reviews, and quality investigations. A nonconformance may be found against an ISO 9001 requirement, an internal procedure, a customer requirement, an engineering specification, or another controlled requirement used by the organization.
In operational use, a nonconformance is often documented in a nonconformance report, or NCR, and may lead to containment, disposition, correction, root cause analysis, or corrective action. It should not be confused with a defect alone. A defective part can be a nonconformance, but a missing record, skipped approval, uncontrolled document, or process deviation can also be a nonconformance.
ISO 9001 commonly uses the term nonconformity, while many manufacturing organizations use nonconformance in day-to-day quality workflows. The practical meaning is similar: a requirement was not met and the issue should be identified, evaluated, and handled through the organization’s quality process.