Wool is an outstanding, multifunctional natural fiber. Its physical and chemical structure makes it valuable since the ancient era of the humanity. However, preparing wool for end use is difficult and complicated, so it needs intensive care on every production step. Its treatment steps start while wool is on fleece form. Among those processes, scouring of raw wool fibers is a strenuous work. Besides this, it is the first step can influence the destiny of the wool for subsequent usages. As it is known, raw wool fleece includes contaminations which can weigh the half or more of the raw wool. Scouring process was managed firstly generally to terminate those impurities. In this study, the effect of ultrasound waves during scouring of raw wool fibers was examined. For this aim wool fleece was scoured consecutively in five washing steps with and without ultrasound. It was found that after third washing step in consecutively ultrasonic washing process, nearly same results provided by the five stepped non-ultrasonic washing regime. Addition to this, the fleece was also scoured separately in different temperatures with only water and with chemicals. Especially the washings at 50 C with ultrasound for 30 min in separate washing regimes was found as an alternative for the non-ultrasonic consecutively washings. On the other hand with the washings at 35 C with only water via ultrasound has shown interesting results too. In general it can be told that application of ultrasound in scouring processes provided improvements in washing efficiency. In other words, addition the ultrasound to scouring processes caused better whiteness degrees and removal of dirties. (C) 2012 Elsevier Ltd. All rights reserved.