Tailing from colemanite concentrators in Emet Boron Works contains significant amounts of boron and cause potential environmental problems. Therefore, the recovery of colemanite from these tailings is imperative to ensure no pollution of the environment. In addition, the tailings also have economic importance as a secondary resource due to their high content of B2O3. This study was undertaken to investigate the possibility of recovering colemanite from tailings using a Knelson concentrator. After samples in size of -1 mm and 0.5 mm were obtained from tailings (-3 mm) by comminution, these three different samples were placed into a Knelson concentrator. In addition to particle size, the effects of fluidization water velocity and bowl speed on the performance of the enrichment process were examined. A concentrate with a B2O3 content of 34.2% was produced with a recovery of 78.3% from tailings with a B2O3 content of 24.8%. Increasing the bowl speed improved the B2O3 recovery. Increasing the fluidization velocity or reducing the particle size adversely affected the recovery percentage. The enrichment process also permitted the removal of any residual As and Fe.