Back to BlogCMMC Assessments

What to Expect When Sitting Down With a C3PAO for a CMMC Assessment: Insights From the Internet

JCJim Carlson (Co-Founder & CEO)
8 min read
CMMC Assessment PreparationC3PAO InterviewsSystem Security Plan (SSP)
Contractor meeting with a C3PAO assessor, reviewing cybersecurity documentation and compliance checklists during a CMMC assessment.

Key Takeaways

  • Preparation is everything. Companies that succeed have strong documentation, clear procedures, and well-organized evidence.
  • The C3PAO is there to assess, not to help. If you do not have the required evidence, you will fail without a second chance.
  • Understanding the process in advance can save time and money. Mock assessments and document traceability matrices can prevent costly mistakes.

Introduction

Preparing for a Cybersecurity Maturity Model Certification (CMMC) assessment with a Certified Third-Party Assessment Organization (C3PAO) can be an intimidating experience. Contractors often wonder what to expect, what assessors will be looking for, and how they can avoid unnecessary delays or failure. To demystify the process, we combed through Reddit threads, industry forums, and YouTube discussions to gather first-hand insights from those who have been through it. As of mid-March 2025, here is what contractors should know about their upcoming CMMC assessments.

Documentation is Your Best Friend (or Worst Enemy)

Assessors consistently emphasize that documentation is the most critical aspect of the CMMC process. One recurring theme in discussions was the importance of linking your System Security Plan (SSP) to supporting documents. A document traceability matrix, which maps CMMC controls to corresponding documentation, can make the assessor’s job easier and reduce scrutiny.

Common pitfalls include:

  • Claiming that security activities occur but failing to provide proof.
  • Using generic policy templates that are not customized for your environment (assessors can spot these immediately).
  • Not having version control or regularly updating security documentation.

It is critical to start with a well organized System Security Plan and a comprehensive document traceability matrix that links each CMMC control to its supporting evidence. For a step by step explanation on how to prepare your documentation and conduct effective internal assessments before the official C3PAO visit, please see our detailed guide on the CMMC Assessment Process and Maintaining Certification. This post covers everything from preassessment preparation and creating a System Security Plan to the importance of self assessments and internal readiness.

The Assessment Process: Conditional Status and POA&Ms

A major takeaway from online discussions is that CMMC assessments require a high level of compliance. However, contractors who meet at least 80 percent of Level 2 requirements may qualify for Conditional CMMC Status. This allows them to proceed with a Plan of Action & Milestones (POA&M) to close any remaining gaps within 180 days. Certain high-impact controls, such as those worth three or five points, must be fully implemented to pass, as these cannot be included in a POA&M.

Companies that assume they can fix issues after an assessment should be cautious. If critical controls are missing, failure is immediate, and a reassessment will be required.

Every Person Speaking to the Assessor Must Be Prepared

Assessors can ask different team members questions, so everyone involved should be well-prepared. Contractors who have been through the process recommend the following:

  • Only answer what is asked. Providing extra information can open the door to further scrutiny.
  • Have an internal guide outlining where to find each required document.
  • Ensure the person speaking has the authority to answer questions within their domain.

The Role of Managed Service Providers (MSPs)

Many companies over-rely on their Managed Service Provider (MSP), believing the MSP handles everything. Assessors have noted that companies often fail assessments because they do not clearly define the shared responsibility between the contractor and the MSP.

A Customer Responsibility Matrix (CRM) is essential for demonstrating which party is responsible for each security control. Without it, companies risk having gaps in their assessment scope.

The Hidden Cost of Poor Preparation

CMMC assessments are expensive, and failing means you must pay to retake the assessment. Companies that have successfully passed note that thorough preparation can reduce assessment costs by as much as 50 percent. The biggest cost factors include:

  • Time spent fixing documentation gaps after an initial failed attempt.
  • The need for additional assessments if documentation or procedures are inadequate.
  • Failing key controls, especially those worth three or five points, which eliminates the ability to use a POA&M to fix deficiencies later.

Internal Assessments Can Improve Readiness

Organizations that conduct internal self-assessments or hire independent consultants before engaging a C3PAO tend to have higher success rates. While not required by the rule, these proactive steps allow companies to identify weaknesses and fix them before an official assessment takes place.

The Backlog is Real, Get in Line Early

As of early 2025, C3PAOs are booking assessments months in advance. One assessor shared that their first availability was not until August 2025, with small and medium-sized businesses making up 60 percent of the demand. With the expected rollout of the 48 CFR rule, demand is expected to surge further.

As the demand for CMMC assessments continues to surge, many contractors find themselves facing significant scheduling delays and a highly competitive assessment booking process. For further insight into how the increased demand is affecting defense contracts and supply chain readiness, please refer to our comprehensive analysis on The Impact of CMMC on Defense Contracts and Supply Chain. This dedicated post explains in detail the challenges of securing an assessment slot and the broader implications for contractors in today's competitive environment.

Conclusion

If there is one thing contractors can learn from those who have already faced a C3PAO assessment, it is this: preparation is the key to success. Understanding what assessors expect, keeping documentation organized, and ensuring all team members are ready to answer questions can make the difference between passing and failing. The CMMC assessment process is rigorous, but with the right preparation, it is possible to pass on the first attempt and avoid costly delays.

Stay tuned, as we will continue updating this guide as new insights emerge. Have questions about getting your documentation in order? The CMMC dashboard can help streamline your compliance efforts, making it easier to track requirements and ensure you are assessment-ready.

Ready to make your next C3PAO assessment a success? Subscribe now to be among the first to access our upcoming portal, the fastest and most coordinated way to manage all your CMMC compliance tasks. With our platform, you can effortlessly collaborate with your team, track compliance progress, and stay assessment ready every step of the way.

Sign Up Now