Ontiveros was reportedly suffering from liver cancer.
She may be best known for playing the convicted murderer of the Tejano singer in the Selena movie. Selena co-star Jacob Vargas was at her bedside last night and tweeted, "My friend Lupe Ontiveros just passed away. May you rest in peace. Thank you for your great contribution to film and TV. You will be missed."
Some of Lupe's long list of other credits include The Goonies, As Good As it Gets, HILL STREET BLUES and DESPERATE HOUSEWIVES -- for which she was nominated for an Emmy. Her Indie Soap Award nomination came for her brilliant work in the web series LOS AMERICANS.
Ontiveros is survived by her husband and three adult children.