The objective of this study was to document functional results and to compare objective and subjective voice measures after endoscopic laryngoplasty with injection of polydimethylsiloxane (PDMS) for the treatment of unilateral vocal fold paralysis, and to verify PDMS biocompatibility in vocal fold. The design used was a longitudinal prospective study. Fifteen patients with unilateral vocal fold paralysis underwent endoscopic injection of PDMS in general anesthesia. Accurate voice evaluation protocol (acoustic and aerodynamics analyses, GIRBAS [Grade, Instability, Roughness, Breathiness, Asthenia, and Strain] scale, videostrobolaryngoscopy, and Voice Handicap Index test) before, after surgery, and at follow-up time was performed. The median follow-up was 21.7 months (range, 6-35). Data obtained were statistically significant. All acoustic, aerodynamics, perceptive, and subjective evaluations showed a significant improvement. No complications due to PDMS were reported. Functional results were found comparable to framework surgery. Endoscopic injection laryngoplasty with PDMS is a safe and long-term option for treatment of unilateral vocal fold paralysis.