STUDY DESIGN: A prospective study was performed in case with cervical spondylosis who underwent anterior cervical discectomy and fusion (ACDF) with titanium or polyetheretherketone (PEEK) cages. OBJECTIVE: To find out which fusion cage yielded better clinical and radiographic results. SUMMARY OF BACKGROUND DATA: Although use of autogenous iliac-bone grafts in ACDF for cervical disc diseases remain standard surgical procedure, donor site morbidity and graft collapse or breakage are concerns. Cage technology was developed to prevent these complications. However, there is no comparison regarding the efficacy between titanium and PEEK cage. METHODS: January 2005 to January 2006, 53 patients who had 1 and 2-levels ACDF with titanium or PEEK cages were evaluated. We measured the rate and amount of interspace collapse, segmental sagittal angulations, and the radiographic fusion success rate. Odom criteria were used to assess the clinical results. RESULTS: The fusion rate was higher in the PEEK group (100% vs. 86.5%, P=0.0335). There was no significant difference between both groups in loss of cervical lordosis (3.2 + or - 2.4 vs. 2.8 + or - 3.4, P=0.166). The mean anterior interspace collapse (1.6 + or - 1.0 mm) in the titanium group was significantly higher than the collapse of the PEEK group (0.5 + or - 0.6 mm) (P<0.0001). The mean posterior interspace collapse was also higher in the titanium group (1.6 + or - 0.9 mm vs. 0.5 + or - 0.5 mm, P<0.0001). An interspace collapse of 3 mm or greater was observed in 16.2% of the patients in the titanium group, compared with zero patients in the PEEK group (P<0.0001). The PEEK group achieved an 80% rate of successful clinical outcomes, compared with 75% in the titanium group (P=0.6642). CONCLUSIONS: The PEEK cage is superior to the titanium cage in maintaining cervical interspace height and radiographic fusion after 1 and 2-levels anterior cervical decompression procedures.