A series of 19 cases of simultaneous bilateral Attenborough Total Knee Replacement is presented. This semi-constrained prosthesis is ideal for this procedure as early mobilization is possible. In comparison to the available series of unilateral replacement, there has been no indication of an increase in any of the usual complications met in this type of surgery. This procedure is recommended for severe bilateral knee arthritis as it not only saves a second anaesthetic, but it helps rehabilitation and reduces the total hospital stay.