Thymomas are frequently diagnosed in domestic rabbits (Oryctolagus cuniculus domesticus). Treatment modalities include radiotherapy, surgery, and chemotherapy. This lecture will compare the chemotherapeutic protocols, outcomes, survival times, and side effects in 20 client-owned rabbits over a 10-year period at a single exotic companion animal specialty hospital in Hong Kong. All rabbits were diagnosed via fine needle aspirate cytology by the same clinical pathologist and received either a CT scan or a thoracic ultrasound. To standardize results, thoracic ultrasounds were performed by the same veterinarian in all patients using the same ultrasound unit. Patients had monthly serum biochemistry profiles, complete blood counts, blood smear evaluations, and thoracic ultrasounds from the time of diagnosis until they died or went into remission. Once in remission, the patients received these same follow-up diagnostics every 2 months until they relapsed or died. Changes in blood work included lipemia, elevated liver enzymes, hyperglycemia, and lymphopenia. In some patients, these changes required adjustment in the chemotherapy protocol, but did cause changes in clinical signs that the owners noted at home.