References that were exported from databases or other reference managers can be easily imported into Zotero.
If exporting from another reference manager, make sure to first export your references by folder. This will allow you to preserve your original organizational structure.
Zotero easily imports the following file formats:
To import citations saved in one of the above formats:
Zotero will create a new collection containing your imported citations.
It's easy to use EndNote and Zotero together and take advantage of the best features of each, or to share Zotero libraries with colleagues using EndNote or vice versa. Both programs can read and write a standard citation file format called RIS, which means references can be converted back and forth with a few clicks.
PDFs and other attachments do not export between programs, however; only citation information.
Zotero to EndNote
To save your Zotero library for importing into EndNote, click File > Export Library in Zotero. Choose RIS as the file type and pick a filename.
In EndNote, click "File" and then "Import." Click the "Choose File" button and select the file you just exported from Zotero. Set Import Option to "Reference Manager (RIS)" and click Import.
EndNote to Zotero
To export your EndNote library for use in Zotero, click "File" and then "Export." Set the output style to "RefMan (RIS) Export" and save it as a text file.
In Zotero, click File > Import. Select the file you exported from EndNote. The new references will be added to a collection named "Imported" followed by the date and time.