Purpose: The purpose of this study was to investigate associations between voice quality and swallowing function in patients treated for oral or oropharyngeal cancer. Methods: Recordings of speech and videofluoroscopy of 51 patients after treatment for oral or oropharyngeal cancer were analysed. Acoustic voice parameters (fundamental frequency (F0), perturbation (jitter %, shimmer %), harmonics-to-noise ratio (HNR), and intensity (extracted from the vowels /a/, /i/, and /u/)) were compared to swallowing function parameters as assessed via videofluoroscopy (oral, oropharyngeal, and total transit time; estimated percent of oral, oropharyngeal, and total residue; oropharyngeal swallowing efficiency (OPSE), and the penetration/aspiration (PA-) scale). Results: Stepwise multivariate regression analyses revealed that jitter, shimmer, and HNR were not associated with swallowing function. Higher voice intensity in all three vowels /a/, /i/, and /u/ was significantly associated with a higher score on the PA-scale (more penetration and aspiration). Higher voice intensity and F0 were significantly associated with lower OPSE. Conclusion: Higher voice intensity was significantly associated with higher amount of penetration/aspiration, and higher voice intensity and fundamental frequency were significantly associated with swallowing inefficiency. Possible explanations may be found in overcompensation by increased laryngeal muscular strength resulting in increased intensity and pitch during phonation. However, the physiology of associated voice and swallowing function is yet unclear, and more research is recommended. © 2013 Springer-Verlag Berlin Heidelberg.