Most event checklists assume one owner. Co-hosting breaks that assumption, and the gaps it leaves are exactly where partnerships fail: the invitation list nobody confirmed was de-duplicated, the lead split nobody wrote down, the run-of-show where both teams thought the other was handling registration. This is a checklist built for two or more hosts — it spends less time on catering and more on the coordination that single-host guides ignore. For the strategy behind these mechanics, start with the co-hosted events strategy guide; this is the execution layer.
6-8 weeks out: lock the partnership
Everything here happens before you book anything. Skip it and you will pay for it in week two.
- Confirm the partner fit. Audience overlap in the right range, complementary (not competing) offerings, a partner whose brand you are comfortable standing beside.
- Agree the goal in one sentence. Both sides should be able to state what the event is for identically. Misaligned goals surface now or at the post-mortem — choose now.
- Write down the cost split. Even, or weighted by contribution. In writing.
- Write down the lead split. Who gets which contacts. This is the single most-skipped step and the most common source of a soured partnership.
- Assign an owner to every workstream. Venue, each partner's invitation list, content, registration, day-of run, follow-up. Every line has exactly one name.
- Name a single decision-maker. Co-hosting by committee stalls. One person breaks ties.
4-6 weeks out: build it
- Book the venue and set the format. Match the format to the goal — see the strategy guide if this is unsettled.
- De-duplicate the combined invite list early. Two partners inviting the same contact twice, with different messaging, looks amateur. Merge and clean the lists before anyone sends.
- Agree the messaging and who sends from where. Co-branded invitations, or each partner inviting their own list with shared copy. Decide whose logo leads.
- Set up shared registration. One source of truth both teams can see — not two spreadsheets emailed back and forth. This is where collaboration-first tooling (Freshmint among others) earns its place; forwarded attendee lists are where co-hosted events quietly drift out of sync.
- Draft the run-of-show with both teams' roles named. Who opens, who facilitates, who handles arrivals.
1-3 weeks out: tighten
- Send invitations and track RSVPs in the shared view. Both teams watch the same numbers.
- Confirm the guest list is balanced. If one partner's audience is dominating registrations, rebalance outreach now while there is still time.
- Pre-assign follow-up ownership per attendee. Decide who from which team owns the next conversation with each guest, before the event — not after.
- Brief both teams on the goal and the talking points. Everyone working the room should know what a good outcome looks like.
- Reconfirm logistics with the venue. Headcount, dietary needs, AV, timing.
Event day
- Both teams arrive early and aligned. A quick huddle on who is covering whom.
- Work the room to the plan, not at random. Make the introductions you came to make.
- Capture context, not just business cards. What each priority guest actually said is what makes follow-up land.
- Resist the pitch. Especially at intimate formats — the room is for conversation, not a sales presentation.
The 72 hours after: where the value is realized
The follow-up is the actual event, and for co-hosted events it has an extra dimension — coordination, so guests do not get two disconnected messages from two companies.
- Execute the pre-assigned follow-up. Each owner reaches their guests with a specific, personal note referencing the real conversation.
- Reconcile and honor the lead split. Distribute contacts per the written agreement. No surprises.
- Run a joint debrief. What worked, what to change, and — the most valuable question — should this become a series? The second co-hosted event is far easier than the first.
The co-hosting-specific failure points
A generic checklist will not flag these, and they are where co-hosted events actually break:
- The lead split was never written down.
- Both teams assumed the other owned registration.
- The invite lists were not de-duplicated, and shared contacts got double-messaged.
- Follow-up was uncoordinated, and guests received two disconnected emails.
If you handle the partnership terms up front and keep one shared source of truth for the guest list, the rest of co-hosted event planning is ordinary event planning. The difference that sinks partnerships is always coordination — so front-load it. For finding the right partner in the first place, see how to find co-hosting partners; for events with several partners, see managing multi-sponsor events.