Background. The aim of this study was to analyze swallowing outcome in advanced oral/oropharyngeal cancer patients treated with microvascular reconstructive surgery and adjuvant radiotherapy. Methods. Eighty patients were included. Patient, tumor, and treatment factors were assessed. Postoperative videofluoroscopic swallowing studies (VFSS) and scintigraphy tests were performed at 6 (n = 54 vs 44) and 12 (n = 32 vs 37) months. Swallowing parameters such as the oropharyngeal swallow efficiency and the Penetration/Aspiration Scale were analyzed. Results. Impaired swallowing status was found at 6 months, which remained stationary at 12 months. Comorbid condition, larger tumors (T3-T4 vs T2), and resections of the base of tongue and soft palate combined (vs defects of other dynamic structures) were associated with most profound swallowing problems (p < .05). Conclusions. Swallowing difficulties are relatively frequent and can to a large extent be predicted. With the knowledge of this study, better counseling and vigilance as to swallowing difficulties may be possible.