Background: Use of autologous fascia, harvested from the thigh fascia lata, has been shown to be effective in the treatment of unilateral vocal fold paralysis (UVFP). However, advantages of this material have been less examined in the clinical setting. The present study aimed to assess the beneficial effects of medialization thyroplasty type I with cadaveric fascia lata on the vocal function of patients with UVFP. Methods: This prospective interventional case series was performed on 10 patients with UVFP, who were candidates for medialization thyroplasty. All the patients were assessed using video stereoscopy to determine the gap and closure of glottis. Voice analysis was also performed. The voice handicap index (VHI) was completed for all the patients. The level of satisfaction with voice quality was also assessed, using the visual analogue scale (VAS). Results: The mean VHI scores significantly decreased at 1, 3, and 6 months after surgery. The mean VAS scores (for voice quality) significantly increased within 1 month after surgery, whereas they gradually decreased at 5 months after surgery. The mean values of minimum and maximum pitch indices were comparable before and after surgery. The mean jitter score decreased at 1 month after surgery, while it remained constant at 6 months after surgery. The mean shimmer score gradually reduced within 3 months after surgery. On the other hand, the mean harmonic/noise ratio (HN/R) significantly increased at 6 months after surgery. The findings showed a significant decline in the frequency of anterior and posterior glottis gaps at all postoperative intervals. Conclusions: Short-term improvement of vocal quality and glottic efficiency, along with reduced glottis gap, is expected following medialization thyroplasty type I with cadaveric fascia lata.