OBJECTIVES: To compare the voice outcome of calcium hydroxylapatite (CaHA) injection laryngoplasty (IL) vs silicone medialization thyroplasty (MT) in the treatment of unilateral vocal fold paralysis (UVFP). DATA SOURCES: Systematic review of English literature from MEDLINE, Google Scholar, Web of Science, Scopus, and the Cochrane library from January 1, 1980, to December 31, 2010. REVIEW METHODS: Included studies reporting voice-related quality of life (Voice Handicap Inventory [VHI]) following IL with CaHA or MT with silicone. The primary outcome measure was the improvement in VHI. The secondary outcome was improvement in maximum phonatory time (MPT). RESULTS: Of the 742 abstracts screened for relevancy, 24 studies qualified for analysis. The mean (SD) VHI scores were 72.22 (11.06) before MT and 34.02 (6.48) after MT. The mean (SD) VHI scores were 68.36 (6.88) before IL and 32.24 (7.33) after IL. The paired difference mean of VHI improvement was 38.20 (95% confidence interval [CI], 17.05-59.32; P = .007) for MT and 36.11 (95% CI, 29.65-42.57; P = .001) for IL. The mean (SD) MPT scores were 7.40 (3.14) before IL and 13.00 (1.75) after IL. The mean (SD) MPT scores were 6.16 (1.90) before MT and 12.40 (2.72) after MT. The paired difference mean of MPT improvement was 6.23 (95% CI, 4.74-7.73; P < .001) for MT and 5.60 (95% CI, 2.95-8.25; P = .006) for IL. CONCLUSION: Injection laryngoplasty with CaHA and MT with silicone appear to achieve comparable voice improvement within 1 year, but a definitive conclusion is limited by a lack of standardized outcome measures.