I’m doing most of my genealogy research on Ancestry.com, because I love their database of information, but I want to be able to create a GEDCOM file from that data so I can use it with the Gramps genealogy program. I can easily figure out how to import GEDCOM into Ancestry using the Upload a GEDCOM button, but I cannot find the place to export the data.
Ancestry.com, like most companies, wants to focus on you using their product as much as possible, so it only makes sense that importing GEDCOM data should be easy. Once you know where to look, exporting a GEDCOM file from Ancestry is fairly easy too. The trick is knowing where to look (which is the part Ancestory could make easier).

Exporting a GEDCOM file from Ancestry in 3 Steps
With your family tree page open, you should see the title of your family tree just below the Ancestry.com menu. Next to the title is a Tree Pages link. When you hover over that link, you get a list of menu options. Choose Tree Settings, which will take you to the page with the GEDCOM export button.

On the right hand side of the Tree Settings page is a list of options. One of those options is Manage Your Tree, which includes a button to export your tree as a GEDCOM file.

When you click the Export Tree button, Ancestry.com will create a GEDCOM file. Depending on the size of your tree, this may take a few seconds or it could take several minutes. When the process of creating the GEDCOM file is finished, you can download the result to your computer.

Once you have the GEDCOM file on your computer, you can import the file into Gramps, webtrees, LifeLine, or any other compatible genealogy application.