This is a case report evaluating the improvement of activities of daily living (ADL) after TKA in stroke patient with hemiplegia and knee osteoarthritis. The case was a 73-year-old female with left hemiplegia caused by cerebral infarction. She also suffered from severe bilateral knee osteoarthritis and obesity. The hemiplegia and knee dysfunction disturbed her ADL. When she was admitted to our hospital, her FIM motor subscore was 23 and body mass index (BMI) was 36.0. She went on a diet and continued rehabilitation. Her knees were treated conservatively. Six months after the stroke, her FIM motor subscore was 35 and BMI was 29.8. For the purpose of pain relief and improvement of range of motion, right TKA was performed seven months after stroke. And left TKA and lengthening of the gastrocnemius were performed eleven months after her stroke. Rehabilitation was continued carefully in order to avoid deep venous thrombosis. In addition, a left obturator nerve block was performed as treatment for spasticity of her hip adductor muscle. Fifteen months after the stroke, her FIM motor subscore was 77 and BMI was 25.7. TKA is a common treatment for osteoarthritis but when a patient has a stroke, it is difficult to determine whether to perform surgery or not. In this case, bilateral TKA achieved improvement of ADL. We suggest that even if a patient has stroke hemiplegia, TKA should be considered for knee osteoarthritis based on the appropriate assessment and careful risk management.