Publicist Teal Cannady said in a statement that the two actors separated over the summer after 23 years together. She did not elaborate.
Sarandon, 63, and Robbins, 51, met while shooting the 1988 film "Bull Durham." They have two sons together.
Sarandon stars in "The Lovely Bones," opening worldwide next month. Robbins last appeared in 2008's "City of Ember."