OBJECTIVE: To study the effect of chairside sandblasting of the bases upon the retention of mesh backed orthodontic brackets. DESIGN: Prospective controlled clinical trial. METHODS: Brackets were bonded to 60 successive patients who were treated at an orthodontic practice in Amman, Jordan. Using a crossover system of allocation, quadrants were bonded using either sandblasted or non-sandblasted brackets respectively. Rely-A-Bond adhesive was used throughout. Bond failures were monitored over one year. RESULTS: 1112 brackets were assessed. The overall failure rate was 4.0% and the failure rates for non-sandblasted and sandblasted brackets were 4.7 and 3.4% respectively. The odds ratio for at least one bracket failure within the control quadrant compared with the experimental quadrant was 0.50 (95% CI 0.185 to 1.238), which was not statistically significant. CONCLUSION: Sandblasting did not significantly improve the retention of mesh based orthodontic brackets in this study.