What Is a C3PAO?

A Certified Third-Party Assessment Organization (C3PAO) is an independent organization accredited by the Cyber AB to perform CMMC assessments on behalf of the Department of Defense. C3PAOs employ certified CMMC assessors who evaluate an organization’s implementation of security practices against the requirements of the target CMMC level. The assessment results determine whether the organization receives CMMC certification, which is required for DoD contracts involving Controlled Unclassified Information (CUI).

How C3PAO Assessments Work

The CMMC assessment process follows the CMMC Assessment Process (CAP) methodology. A C3PAO assessment team evaluates the organization’s System Security Plan (SSP), reviews evidence of control implementation through documentation review, technical testing, and personnel interviews, and scores each of the 110 NIST SP 800-171 practices as MET, NOT MET, or NOT APPLICABLE. The lead assessor then submits the assessment report to the Cyber AB for quality review and final certification decision.

C3PAO Accreditation Requirements

To become an authorized C3PAO, an organization must complete the Cyber AB’s rigorous accreditation process, which includes demonstrating their own CMMC Level 2 compliance, maintaining ISO 17020 accreditation for inspection bodies, employing certified CMMC assessors who have completed required training, passing Cyber AB quality assurance reviews, and maintaining independence from the organizations they assess to prevent conflicts of interest.

Choosing a C3PAO

Defense contractors preparing for CMMC certification should select a C3PAO by checking the Cyber AB Marketplace for the current list of authorized C3PAOs, verifying the C3PAO’s experience with similar-sized organizations and industry sectors, confirming assessor availability and scheduling timelines, understanding the C3PAO’s communication process and evidence submission requirements, and requesting references from other organizations the C3PAO has assessed.

C3PAO vs. DIBCAC Assessments

C3PAOs and DIBCAC both evaluate contractor cybersecurity, but serve different purposes. C3PAO assessments result in a formal CMMC certification level and are required for new contracts containing DFARS 252.204-7021. DIBCAC assessments evaluate compliance with existing DFARS requirements and produce SPRS scores. In some cases, contractors may undergo both types of assessment as the DoD maintains parallel oversight mechanisms during the CMMC transition period.