Version v201008 of the AdWords API introduces UserListService and CriterionUserList which give you API access to the features available in the "Audiences" tab in the AdWords interface. To learn more about remarketing, visit AdWords Help Center, or watch the video below:
You can set up remarketing using the AdWords API in two steps:
- Create a remarketing list.
- Create a CriterionUserList to tie your list to an AdGroup.
More Info: Discover v201008: Remarketing