This chapter familiarizes the readers with the principles of stoma creation and selecting the stoma site. The objective of stoma construction is to provide an anatomically stable opening allowing placement of an ostomy management system that will maintain a seal of stool and gas for 4–7 days. The stoma must be constructed so that it is visible to the patient. It should be located away from the umbilicus, skin creases, scars, and bony prominences. Areas of skin damaged by irradiation or skin grafts also should be avoided. The first step in the construction of enterocutaneous stoma is the selection of appropriate site. Stomas should be located within the rectus muscle; if the stoma is brought outside the rectus muscle, the incidence of parastomal hernia is very high. To select the correct site for the stoma, the assessments should be made preoperatively which are type of stoma anticipated, the rectus muscle sheath, adequate surface area, easily seen, smooth skin surface, and marking the site.