She made the announcement on Instagram with a heartfelt message paired with a picture of herself smiling.
"Beautiful friends, I want to share with you that this last week I was diagnosed with breast cancer," she wrote.
Crenn acknowledged that one in eight women have breast cancer, and shared a token of inspiration for them too.
"For all the women who have been on this journey before me and now with me, my heart is with you," she wrote.
Crenn says she is going to remain in her kitchen as much as possible while she fights the disease.
She has three restaurants in San Francisco, Atelier Crenn, which won a Michelin award, Petit Crenn and Bar Crenn.