Although bimaxillary surgery enhances patients' self-esteem and mood by improving their facial appearance, surgical outcome assessments for this procedure are limited. This preliminary study investigated differences in brain activity on functional magnetic resonance imaging (fMRI) during self-face evaluation before and after bimaxillary surgery. Three patients (1 man and 2 women, age range: 20–27 years) underwent fMRI while viewing self-face images before and after bimaxillary surgery for maxillofacial deformity. The activation in the left postcentral gyrus, and medial orbital frontal cortex was significantly great in response to after-surgery self-face images compared to before-surgery images. Our preliminary results may facilitate the development of an objective measure for patient satisfaction after orthognathic surgery including bimaxillary surgery.