The Office star said that she was first diagnosed with stage one triple-positive breast cancer last December.
Fischer who starred as receptionist Pam Beesley in the US version of The Office alongside Steve Carell and John Krasinski, released this statement on Instagram.
"After completing surgery, chemotherapy, and radiation I am now cancer-free", she said.
Having undergone her routine mammogram, Fischer's results came back inconclusive, with a biopsy subsequently ordered, which found the "aggressive form of breast cancer".
"In January, I had a lumpectomy to remove the tumour," she added. "Luckily my cancer was caught early and it hadn't spread into my lymph nodes or throughout the rest of my body, however because of the aggressive nature of the triple-positive breast cancer it still required chemotherapy and radiation to be sure it didn't return".
Fischer explained that she had12 rounds of chemotherapy in February and three weeks of radiation in June.
"I lost my hair during chemotherapy but thanks to some great wigs and hats with hair (which my family affectionately called Wigats) I have been able to wait until now to reveal all that has been going on for me," she said.
Jenna Fischer also paid homage to her best friend and co-star Angela Kinsey as she "protected me and advocated for me" as the pair recorded their podcast Office Ladies.
"For a long time, she was the only person in my workspace who knew," she said. "When I lost my hair, she wore hats to our work meetings so I wouldn't be the only one. When I needed a break, we took one".
Jenna also paid tribute to her husband and filmmaker Lee Kirk who was "by my side through all of this".
Fischer concluded her statement by saying: "don't skip your mammogram", and "Michael was right. Get 'em checked ladies".
Fischer celebrated the end of her cancer treatment with her husband and their two children aged 10 and 13, by ringing a bell and throwing confetti in their back garden.
