Three cases of cystic tuberculosis of the patella are presented. Two of them were seen with a cyst-like cavity under intact articular cartilage. A long postoperative follow-up in both cases showed full recovery and preservation of knee function after removal of the patella. The third case showed an extensive destruction of the patella and of its articular cartilage. Although the progress of the disease was controlled by surgery and adequate medication, the function of the knee did not fully return.