The objective of this work was to investigate the effect of ultrasounds (US) on the flux recovery of ultrafiltration (UF) membranes fouled with bovine serum albumin (BSA) solution. Chemical cleaning was carried out with NaOH solution. The effect of ultrasonic frequency in the cleaning step was evaluated. Tests were performed in a laboratory plant equipped with a flat sheet module for two membranes. The membranes used were UH030 and UP005. Results showed that the lowest US frequency was the most effective one, producing an enhancement of 9-12% in the flux recovery of the membranes. On the other hand, neither pH nor temperature proved to be significant factors on the flux recovery. The use of US technique is an effective and promising approach to clean UF membranes after being fouled with BSA solution and may have a relevant influence on the overall process efficiency. (C) 2013 Elsevier B.V. All rights reserved.