The flotation performance is associated with the probability of bubble-particle collision and the aggregate stability. Currently, one of the major challenges of the mining industry is the flotation of fine particles and the generation of medium-sized bubbles (100-1000 mu m) can be a good alternative to increase the recovery of these particles. Therefore, new strategies to determine and control bubble sizes, to achieve the desired diameters are very important. This study aimed to characterize and control the bubble size distribution and to consider its relation with the flotation performance. Two different methods (offline and online) were used to measure the bubble size distribution. The results showed that the addition of surfactant was a good alternative to generate bubbles with high percentages of medium-sized bubbles (80-90%) and high air hold-up values (10-12%), simultaneously. Kinetic test showed a direct relation between the bubble size distribution and the P2O5 content. (C) 2016 Elsevier B.V. All rights reserved.