Her death comes just hours after the 43-year-old revealed on social media on Friday night that she was receiving palliative care.
She then asked her followers to look out for her children, Jacob and Eva, whom she described as “the kindest, sweetest, most thoughtful kiddies.”
Her parents, Noel and Maura, also survive.
“The UTV family is deeply saddened to hear of the passing of former colleague and friend Aideen Kennedy,” a UTV spokesperson said.
She was a truly gifted reporter who worked for UTV for many years, bringing viewers stories from all over Northern Ireland.
“We wish to express our heartfelt condolences to her family during this difficult time.”
Ken Reid, a former UTV political editor, was among those who paid tribute to his former colleague.
“The thought [Aideen] is no longer with us is just heartbreaking,” he said. A good person who suffered far too much.
“Aideen was always lovely to meet out while covering a story,” said BBC weather presenter Barra Best.
Politicians, including the DUP’s Emma Little Pengelly, have also paid tribute to the late journalist.
“No more pain or illness for you now,” said the Lagan Valley MLA. There will be no more pain or trauma. “The most beautiful, kind soul that life has given me the honour of knowing.”