The present invention relates to a dialyzer holder to attach a dialyzer to a dialysis machine. During priming of a bloodline prior to a dialysis treatment, the dialyzer holder grips a dialyzer in approximately the center of the dialyzer, but allows movements of the dialyzer in an arc motion using two axes of rotation. The holder enables the dialyzer to move to a position where air can be primed from the dialyzer and, because the dialyzer can move toward the dialysis machine, this motion eliminates stress on the tubing connected to the bottom and top of the dialyzer and reduces the length of bloodline tubing necessary to accommodate dialyzer movement. The dialyzer holder incorporates an attachment point for a venous chamber for use during the priming procedure, enabling the venous chamber to move with the dialyzer, further reducing the tubing between the dialyzer and the venous chamber.