Syncing Leads on Mass from Salesforce to Marketo

[Anonymous]

HI there,

I have a number of leads in my Marketo which sync through to my salesforce and have the standard bidirectional sync.

However I have another 30,000 leads which were input straight into Salesforce, and therefore are not in Marketo. I want to mass sync these to Marketo, and was wondering if anyone new best practice?

Do I just download and add them via CSV? Or is there a more efficient method?

[Josh_Hill13]

They should sync to Marketo automatically unless they are blocked for some reason.

If you post them back to Marketo via List Upload, then you will create dupes.