The former British number one released a statement about her illness today.
She announced her retirement from tennis last year at the age of 30.
The statement said: "I have recently been diagnosed with cancer of the liver. I'm currently undergoing treatment and fighting this illness with everything I have."
Baltacha won 11 titles during her career despite being diagnosed at 19 with primary sclerosing cholangitis, a chronic liver condition that compromises the immune system.
She broke into the world's top 50 at her peak and is the highest-ranked female singles player Scotland has ever produced. She twice reached the third round of the Australian Open and made the same stage of Wimbledon in 2002.
Baltacha and her husband Nino have thanked everyone for their continued support following her diagnosis.