The use of proper knot tying technique is needed to ensure good results in dermatologic surgery, but complications of suturing remain. In this study, we evaluated the knot tying process of skin sutures and buried sutures and investigated the relationship between the orientation of the square knots and the knot tying direction. We demonstrate that the orientation of the square knot and strand ends is determined by the pulling direction of the first loop tying. We also suggest the proper orientation of square knots for different kinds of suturing and illustrate the proper knot tying techniques. Finally, we recommend an oblique oriented buried suture, which is more secure and easier to perform than traditional buried sutures.