The fourth season of Madam Secretary an American political drama television series originally aired in the United States on CBS from October 8, 2017, through May 20, 2018.

Madam Secretary was renewed for a fourth season on March 23, 2017.

[23] Bebe Neuwirth left the cast after the third episode of the season.

[24][25] Sara Ramirez joined the cast as Kat Sandoval as a series regular.

Hall said of Ramirez: "She brings a fresh perspective and a fun, energetic quality to the State Department staff.