What a PCO Is
A professional congress organiser is the company that runs a conference or congress end to end — the programme, the abstracts, the registration, the delegate numbers, the exhibition floor, the sponsors and the budget. It is hired by the body whose congress it is, and it usually stays with that congress from year to year, wherever it is held. A DMC is a different animal: it is based in one country and signs the contracts with the suppliers there. A PCO frequently engages one.
What a PCO does
A professional congress organiser runs a conference. Not the venue and not the travel — the conference itself.
Take a European cardiology society holding its annual congress in Athens for 4,000 delegates. Somebody has to build the scientific programme, collect and referee several thousand abstracts, run the registration system and take the money, allocate the rooms to the sessions, sell and lay out the exhibition floor, manage the sponsors, brief the speakers, print the badges, and hold the whole budget. That is the PCO.
The name says congress, and the work is congress work: a paying audience, a programme, an exhibition, and a set of accounts that has to balance. It is a different discipline from staging a dinner or moving a board around a country.
Who hires a PCO, and for how long
The body whose congress it is. An association, a learned society, a professional college, a company running its own user conference.
That relationship is often long. A society whose congress moves between cities may keep the same PCO across several editions, because what the PCO holds is the institutional memory of the event — the delegate database, the sponsor relationships, the abstract system, the financial history. The city changes; the congress does not.
The trade calls the version of this arrangement that spans years a core PCO. The distinction that matters for a buyer is simpler: some PCOs are hired for one edition in one city, and some are hired for the congress itself.
PCO and DMC
The two words are used interchangeably by people who are not in the trade, and by a few who are. They are different jobs, and the difference is what each one signs.
| What it organises | Where it sits | What it signs | |
|---|---|---|---|
| PCO | The congress — programme, registration, delegates, sponsors, budget | Anywhere. Often not in the host country | The organiser’s contract with the association, and the delegate-facing arrangements |
| DMC | The ground — transport, venues, dinners, staff, excursions | In the country the event is held in | Contracts with the local suppliers, in its own name |
A PCO running a congress in a country it does not operate in will frequently engage a DMC there to do the ground work. The DMC signs for the coaches, the gala venue and the offsite dinner; the PCO stays responsible for the congress.
Plenty of companies do both, and a good many Greek firms do. That is not a criticism, and it is often the efficient arrangement. It does mean that the label on the website says less than the contract does — which is the same lesson as what a DMC is, for the same reason.
What accreditation actually means
Two bodies are worth knowing about, and they do different things.
IAPCO, the International Association of Professional Congress Organisers, is the global accreditation body for the trade. It has more than 95 member companies operating from over 187 offices, and its members reported delivering 23,512 meetings and events in 2025, for 7.7 million participants. Membership is an accreditation, not a subscription.
HAPCO, the Hellenic Association of Professional Congress Organizers, is the Greek association, and its published criteria for full membership as a PCO are unusually specific. A company must show:
- at least 2 years of lawful operation;
- a dedicated office of at least 60 square metres, with conference management software and the hardware to run it;
- a minimum of 6 full-time employees, including one university graduate and two holding tourism qualifications;
- gross revenue of at least €1,500,000 over two years, and paid-up capital of at least €60,000;
- an ISO quality certification;
- leadership with documented experience — the criteria name organising 10 or more conferences of 300 or more attendees each within three years;
- clearance on bankruptcy and on relevant criminal convictions.
Read that list as what it is: a floor. It does not describe a good PCO. It describes a real one, with staff, a balance sheet and a track record that can be counted. A company that cannot meet a threshold this ordinary is telling a buyer something.
The part buyers most often miss
A PCO that also books your flights, your transfers and your hotel rooms is selling travel services, and selling travel services in Greece is a separately regulated activity. A company doing it must notify the authorities and lodge a guarantee of €5,000 in favour of the Greek State — the same regime that governs any Greek travel agency or DMC.
So the useful question is not whether a company calls itself a PCO. It is which of the two things it is doing for you, and whether it is authorised for the second one.
What to ask before appointing one
Four questions, and the answers should come back with numbers in them.
- Which parts of this are you doing, and which are you subcontracting? A PCO that subcontracts the entire ground operation is coordinating a DMC, and you should know who that DMC is.
- Who holds the delegate registration money, and in what account? Registration income is the delegates’ money before it is anyone’s revenue.
- What are your last three congresses of comparable size, and what were the final delegate numbers against forecast? A PCO that has run them answers with figures. The gap between forecast and actual is the most informative number in the trade.
- If we are also buying travel, are you licensed to sell it here? A straight question with a documentary answer.
The third question is the one that separates firms. Every PCO has a forecast. Not every PCO will show you how the last three turned out.