A contract manufacturing organization (CMO), sometimes called a contract development and manufacturing organization (CDMO), is a company that serves other companies in the pharmaceutical industry on a contract basis to provide comprehensive services from drug development through drug manufacturing. This allows major pharmaceutical companies to outsource those aspects of the business, which can help with scalability or can allow the major company to focus on drug discovery and drug marketing instead.

Services offered by CMOs include, but are not limited to: pre-formulation, formulation development, stability studies, method development, pre-clinical and Phase I clinical trial materials, late-stage clinical trial materials, formal stability, scale-up, registration batches and commercial production. CMOs are contract manufacturers, but they can also be more than that because of the development aspect.

Their customers are not only expecting competitive pricing but also regulatory compliance, flexibility on the production capability and on time delivery. Overall it is required that CMO complies with good manufacturing practice from their client and regulatory bodies such as Food and Drug Administration.