Choosing a contract manufacturer is the highest-consequence sourcing decision most drug programs make. A wrong pick surfaces late — during tech transfer, a pre-approval inspection, or a launch-quantity scale-up — when switching costs are at their peak. This guide is the selection framework we see disciplined sourcing teams actually use, in the order they use it.
Last updated August 4, 2026
Most bad CDMO selections are decided before a single supplier is contacted, by starting from a list of names instead of a specification. Write these down first — they are what turns a vague search into a filter, and they are what a serious CDMO will ask for on the first call anyway.
A shortlist built from this specification is defensible. A shortlist built from brand recognition is not.
Capability and capacity are different questions, and conflating them is one of the most common sourcing errors. Capability asks whether the site can perform the operation at all. Capacity asks whether it can perform it for you, in your window, at your volume. A CDMO can be a genuine expert in your process and still be the wrong answer because the relevant suite is fully booked for eighteen months.
Test capability with evidence, not with a capabilities deck: ask which specific suite and equipment train would run your product, how many campaigns of this type it has run in the last twenty-four months, and whether the process was developed there or transferred in. Then test capacity separately: ask what is currently booked in that suite, what the realistic slot is, and what a reservation would cost. A partner who answers the second question vaguely is telling you something.
Below are the capabilities most frequently listed across the CDMO Hub directory, with live counts. Use them as a starting filter — then verify the specific claim at the specific site.
Live counts of CDMOs listing each capability in the CDMO Hub directory.
A facility’s inspection history is the single most objective quality signal available to a buyer, and it is largely public. Treat it as a required diligence step rather than a nice-to-have, because it is the one input that does not come from the supplier’s marketing.
For US-relevant sites, the FDA classifies the outcome of each inspection into three categories. **NAI** (No Action Indicated) means no objectionable conditions were found. **VAI** (Voluntary Action Indicated) means objectionable conditions were found but the agency is not prepared to take or recommend action — these are common and are not automatically disqualifying. **OAI** (Official Action Indicated) means regulatory or administrative action is warranted; an OAI classification on a site you intend to use is a material finding that requires explanation and evidence of remediation. Ask for the establishment inspection report, the Form 483 observations, and the company’s responses — a confident partner shares them.
Look at the pattern, not a single data point. Repeat observations across consecutive inspections in the same system — particularly data integrity, aseptic practice, or investigations and CAPA — indicate an unresolved systemic issue rather than an isolated finding. Also check recency: a clean record from an inspection five years ago says much less than a recent one, especially if the site has changed ownership, expanded, or added a new product type since.
Outside the US, the equivalent signals are EU GMP certificates and any non-compliance reports published in EudraGMDP, the national competent authority’s findings, PMDA status for Japan, and membership of the PIC/S scheme. Confirm that the certificate covers the specific dosage form and operation you need — site-level certification does not imply every activity at that site is covered.
Finally, verify at the site level, never the corporate level. A group can hold an excellent overall record while the specific facility that would make your product has a different history. Inspection records attach to establishments, and so should your diligence.
Every site visit looks impressive. The quality system is what determines whether the site performs on a bad day, and it is assessed through documents and behavior rather than through the walk-through. Ask for these specifically:
Tech transfer is where selection decisions are proven right or wrong. The capability existed, the contract was signed, and the program still slips two quarters because the process did not behave the same way in the receiving site. Assess transfer risk explicitly, as its own criterion, before signing.
Ask how the CDMO runs a transfer: whether there is a defined protocol with acceptance criteria agreed in advance, who the named technical lead is, whether engineering or demonstration batches are planned before GMP material, and how analytical methods are transferred and co-validated. Method transfer is the step most often underestimated — a process that transfers cleanly can still stall for months on an analytical method that will not reproduce in the receiving lab.
Probe the gap between the originating and receiving equipment. Differences in mixing geometry, heat transfer, filtration area, hold times, or single-use versus stainless contact materials are where a robust process quietly becomes a variable one. The right answer to "will this scale?" is a comparability plan, not reassurance.
Ask for references from transfers of a comparable modality and scale — and ask specifically about one that went badly. How a partner describes a difficult transfer, what they attribute it to, and what they changed afterwards tells you more about how they will handle your problem than any successful case study.
Agree up front what happens when the transfer misses its criteria: who pays for repeat batches, how the timeline is re-planned, and what the exit path looks like. Exit terms are cheapest to negotiate when neither side expects to need them.
Price per batch is the least important commercial term. What determines total cost and flexibility is the structure around it:
For commercial programs, plan for dual sourcing or at least a documented second-source path. Single-sourcing a commercial product is a business continuity decision, and it should be made deliberately rather than by default.
Geography affects far more than unit price. It determines travel time for person-in-plant and audits, time-zone overlap for the daily problem-solving that a transfer requires, shipping lanes and cold-chain risk, import and export licensing, and which regulatory authority inspects the site. A lower quoted price with a twelve-hour time difference and a two-day travel commitment is not obviously cheaper once a program hits a problem.
Manufacturing capacity is genuinely global, and concentration varies sharply by modality — sterile fill/finish, API synthesis, and cell and gene therapy have different maps. The live facility distribution across the CDMO Hub directory is shown below.
Manufacturing facilities recorded in the CDMO Hub directory, by country. Explore the full facilities map.
None of these is automatically disqualifying on its own. Each one warrants a direct question, and a partner who cannot answer it comfortably has told you something useful.
Reluctance to share inspection history
Form 483 observations, responses, and EU GMP certificates are ordinary diligence requests. Hesitation, heavy redaction, or "our policy is not to share that" is the strongest single signal on this list.
Capability confirmed only at corporate level
The answer names the group, not the site, suite, or equipment train that would run your product. Ask which building. If that cannot be answered specifically, the capability may not exist where you need it.
No named technical lead
Business development is responsive and technical contact is scarce. The relationship you actually depend on is with the process and quality people; if you cannot meet them before signing, you are buying a sales process.
Every answer is yes
A partner who claims to do every modality, every scale, and every dosage form, on your timeline, with no trade-offs, is either not listening or not being straight. Good CDMOs decline work that does not fit them.
Vague or absent capacity answers
Unwillingness to state what is booked in the relevant suite, or a slot that keeps moving between conversations, usually means you are being fitted around a larger customer.
Quality agreement deferred
"We will sort the quality agreement after signature" concedes the terms you most need. Deviation ownership, notification, and audit rights get harder to negotiate once the program is committed.
Recent unexplained change
A change of ownership, a site closure, a leadership exit in the quality unit, or a major expansion — not disqualifying, but each changes the risk profile and should be discussed openly rather than discovered.
Where you see ranked lists or Evidence Scores on CDMO Hub — best-of lists, country pages, and company intelligence profiles — the ranking is computed from the same public regulatory record covered in section 03, never from vendor submissions. Read the full methodology for every input, weight, and eligibility gate.
Tick what a candidate supplier has confirmed in writing.
Future: send this checklist as an RFI to shortlisted CDMOs directly from your dashboard.
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