We describe a reproducible, step-by-step arthroscopic technique for anchorless transosseous rotator cuff repair using an X-box configuration with the Arthrotunneler device. The technique uses 2 bone tunnels and 4 high-strength sutures and is suitable for medium to large tears of the supra- and infraspinatus that would alternatively need a double-row repair with 4 anchors. Biomechanically, results appear to be similar as for anchored transosseous equivalent techniques. Enhanced biological healing and lower material costs are the possible benefits of this appealing arthroscopic approach that mimics the previous gold standard.