In brief
MRO stands for maintenance, repair and operations and covers all goods and services that keep a plant running, serviced and repaired.
Contents
What is MRO?
The abbreviation MRO groups together materials and services that do not go into the end product but are needed for the ongoing operation of a plant. These include spare parts and wear parts such as bearings, seals, valves or sensors, as well as operating supplies, tools, personal protective equipment and maintenance services. In aviation the O often stands for overhaul, meaning a complete rebuild; in industry, operations is the usual reading.
From a business perspective, MRO is part of indirect spend. It typically involves a very large number of items with low unit value, irregular consumption and numerous suppliers. The value of an MRO part is therefore rarely measured by its price, but by the consequences when it is missing: a bearing costing a few euros can bring a production line to a standstill.
Key metrics in the MRO environment are availability, replenishment lead time, stock levels and process costs per order. Many companies therefore pool requirements, standardise item master data and define which parts are critical and must be kept in stock.
In practice: maintenance and procurement
In maintenance, MRO work starts with clean part identification: manufacturer part number, nameplate and installation situation. In procurement, it pays to rank MRO requirements by criticality rather than managing them like direct materials purely on unit price.
Synonyms and abbreviations: maintenance, repair and operations · maintenance, repair and overhaul (aviation) · MRO supplies · MRO materials
Frequently asked questions
What does MRO material include?
MRO material includes everything that keeps a plant running without becoming part of the product itself: bearings, seals, belts, filters, valves, sensors and drive components, as well as lubricants, cleaning agents, tools, measuring equipment and personal protective equipment. External maintenance and repair services are often included too. Each company defines the exact scope in its own category structure.
What is the difference between MRO and direct materials?
Direct materials go straight into the manufactured product, such as raw materials or bought-in parts, and can usually be derived from production plans. MRO material, by contrast, keeps the equipment running. Demand for it arises from wear, servicing intervals or breakdowns and is therefore harder to plan. The control parameters differ accordingly: for direct materials, quantity and price; for MRO, above all availability and fast identification.
Why is MRO so important for companies, even though the parts are often inexpensive?
The value of an MRO part only becomes apparent when it is missing. An inexpensive wear part can stop an entire line, and the downtime costs then exceed the price of the part many times over. On top of this come the process costs: many small orders with many suppliers cause considerable effort. A well-considered MRO strategy therefore aims at the availability of critical parts and lean processes, not just low unit prices.