BACKGROUND In the fall of 2005, the University Health Network in Toronto, Canada, initiated a policy requiring the surgeon-or his or her delegate-to sign the incision site for all operations. Little is known about what health care providers and patients think about official surgical site marking policy. METHODS Twenty-one patients and health care providers were interviewed, and the authors conducted field observations of surgeons while they marked their patients. The data were analyzed using grounded theory methods. RESULTS Surgical site marking was perceived to be a safety precaution for operations involving multiple sides and structures but not for cases where there is no uncertainty about the intended operative site. Participants believed that marking could also facilitate error if the wrong side was marked. Site marking was perceived to have the effect of ensuring that the surgeon meets with the patient prior to the operation on the day of surgery. Concerns were raised with respect to who should mark patients and marking surgical sites for genital surgery or other private body sites. CONCLUSIONS For operations that involve multiple possible surgical sites, site marking should be carried out by individuals who are knowledgeable about the patient and the proposed procedure. For operations in which there is no uncertainty about the intended site, interventions other than site marking could be implemented to ensure patient-surgeon interactions on the day of surgery. Surgical site marking procedures should respect patient dignity and privacy.