When you import a list into Marketo and sync to Salesforce.com as contacts is there a way to NOT create an opportunity?

This sounds more like a problem with your SFDC settings than anything to do with the Marketo side of things. You'd have to check your rules behind contact/account creation and see if it automatically generates a new opportunity.

By default, adding contacts in Marketo should not be generating opportunities. Matt is right. You might have a command in SFDC that auto-created opportunities when a new contact is added

Are you by chance using the 'convert' function in marketo to sync them over as contacts? Doing that will indeed create a new opportunity/account in salesforce for each person converted.

Thanks for all the help!! We're taking over an existing instance of Marketo/SFDC for a client, so trying to figure out what's happening.

SFDC setting don't show any auto-created opportunities. There is a 'Lead Source' field which is mapped from lead to contact to opportunity. This field was included in the list upload to Marekto so I'm thinking that may auto-create an opportunity when a new contact is created.

Caleb - We are using the convert function. Screen shot  below. If that is the cause, is there a way to bypass creating an opportunity? OR a better way to import as contacts? To give you background, these leads have been pre-qualified as part of a paid media effort, which is why we want to sync over as contacts vs. having them sync over as leads.