Unilateral vocal fold paralysis can result in incomplete glottic closure, compromising the vocal efficiency and increasing the risk of aspiration. The glottic gap can be reduced by medialization thyroplasty. Both silicone and titanium implants have been described to be efficient in the improvement of the vocal outcome. The aim of this study was to assess the vocal outcome after medialization thyroplasty using silicone and titanium implants and to compare the results of the two implanted materials using prospective sequential cohort study. 24 patients underwent medialization thyroplasty, performed under local anaesthesia with intravenous sedation: 10 patients were included in the silicone cohort and 14 in the titanium cohort. All patients underwent vocal assessment preoperatively and postoperatively, using the Voice Handicap Index, the GRBASI scale, maximum phonation time and the Dysphonia Severity Index. Postoperative analysis of the entire population showed statistically significant improvement for the Voice Handicap Index, maximum phonation time, Dysphonia Severity Index and the parameters G, B and A of the GRBASI scale (83% follow up). Subgroup analysis showed a statistically significant greater improvement of Voice Handicap Index of the titanium cohort compared with the silicone cohort. Improvement of maximum phonation time, Dysphonia Severity Index and GRBASI scale of the titanium cohort was greater than improvement of the silicone cohort, but this difference was not statistically significant. Both silicone and titanium medialization implants showed improvement of vocal outcome, the results of the titanium implant being superior.