The surgical orientation system is used to assist a surgeon to orient a prosthetic component relative to a patient's anatomy during surgery. An embodiment is particularly suited for assisting surgeons to locate an acetabular cup into a reamed acetabulum. The system includes: an implement (1) for releasable attachment of a prosthetic component； an electronic orientation monitor (2) attached to the implement (1)； and a brace (3). The brace (3) is releasably attachable to the patient so as to define a reference point (4) relative to the patient's anatomy. This reference point (4) is external of the patient and includes at least one surface (5) defining a reference plane that is used to orient the monitor (2) into a reference orientation to calibrate the monitor (2). The surgeon then manipulates the implement (1) so that the prosthetic component is in the desired position relative to the patient and the monitor (2) provides an indication to the surgeon when a subsequent orientation of the monitor (2) has a predefined relationship relative to the reference orientation； for example the predefined relationship may be parallel to within predefined tolerances. Upon receiving the indication the surgeon inserts the prosthetic component into the patient.
