Three-dimensional (3D) printing is increasingly being used to visualize relationships of anatomical structures and is becoming more popular in planning cardiac procedures.1 3D printing of the coronary sinus (CS) and its branches has not previously been described. The value of 3D models could be particularly high in the planning of cardiac resynchronization therapy (CRT) device implantation where procedural difficulty is anticipated. CRT implantation can be challenging in patients with congenital heart disease and other structural heart abnormalities where the anatomical relationships are complex. A precise 3D model can be beneficial for planning CRT implants to clarify essential anatomical details such as size of the right atrium, angulation of the CS take-off, and location of CS branches and their relationship to the systemic ventricle. We describe the use of a 3D printed model to assist in CRT lead implantation in a case of congenitally corrected transposition of the great arteries (ccTGA). The accurate representation of the CS and its branches helped the operators preselect an appropriate target branch and specific equipment required.