The "Veep" star announced the milestone in an Instagram photo, where the hilarious actress is donned in a black hoodie, sunglasses and a fake mustache.
"Chemo #2: finito. We are NOT f---ing around here," she began in a caption.
Louis-Dreyfus, 56, has apparently drawn inspiration from music in her fight against breast cancer. She quoted Katy Perry's 2013 hit song, "Roar," in her caption as well.
"'I’ve got the eye of the tiger,'" the actress wrote. "'The Fighter dancing through the fire cuz I am a champion and your’re going to hear me ROAR.'"
She then thanked Perry along with her "Veep" co-stars, Tony Hale and Timothy Simons "for their hilarious and loving inspiration."
The Emmy Award-winner announced her cancer diagnosis on Instagram last month.
"1 in 8 women get breast cancer. Today, I’m the one," her announcement read. "The good news is that I have the most glorious group of supportive and caring friends, and fantastic insurance through my union. The bad news is that not all women are so lucky, so let’s fight all cancers and make universal health care a reality."
The Hollywood Reporter noted that Louis-Dreyfus received her diagnosis on Sept. 17 -- just one day after she received the Emmy Award for best actress in a comedy series for "Veep."