Users new to Zotero may find the prospect of importing all their data somewhat daunting. Many researchers already have a large collection of PDFs that they've previously organized manually or using another program. Zotero makes it easy to import these PDFs and retrieve full bibliographic metadata (for searching, citing, indexing, and organizing), taking much of the pain out of switching.

Follow these steps to use the Retrieve Metadata for PDFs function:

1. Drag your existing PDFs into your Zotero library or use the “Store Copy of File” or “Link to File” options from the add new item menu (green plus sign).
2. By default, Zotero will automatically retrieve metadata for PDFs and rename the associated files. If you prefer, you can disable these automatic functions in the General pane of Zotero preferences.

If you have disabled automatic metadata retrieval or have other PDF files already in your library, you can also retrieve metadata manually:

1. In the middle pane, select the PDFs you want to retrieve metadata for.
2. Right-click on the PDFs and select “Retrieve Metadata for PDFs”.
3. If Zotero can find a match for the item, it will create a full Zotero item with the available data and attach the PDF.
4. If Zotero can't find metadata for an item, you can right-click on it and choose “Create Parent Item” to manually enter the item metadata.

With this feature, there should be no major hurdles to switching to Zotero and taking full advantage of all its powerful search, indexing, organizing, and citation features.

The Retrieve Metadata feature uses a Zotero web service to find item metadata. The Zotero client sends the first few pages of a PDF to the web service, which uses a variety of extraction algorithms and known metadata from CrossRef, paired with DOI and ISBN lookups, to build a parent item for the PDF. The Zotero lookup service doesn’t require a Zotero account and doesn’t log any data about the content or results of searches.

While this feature can greatly facilitate importing large existing libraries of PDFs, it is not the best way to add items to your library in general. Items can be imported faster by using the Zotero Connector plugin in your browser from publisher websites or most scholarly databases. This saves several steps versus downloading the PDF manually and adding it to Zotero. The item metadata will also often be higher quality. See Getting Stuff into your Library for the best ways to add items to your library.