The effect of sodium hydroxide in neutralization was increased by using various adsorbents. NaOH in various concentrations was attached to the particles of Kieselguhr, Celite and Bentonite. The neutralization reaction was performed at ambient temperature, and different reaction times were applied. The soap formed after reaction was removed by centrifugation; thus, washing and drying steps were omitted. The amount of remaining soap, the acidity and color of oils were determined after each treatment. According to the results, free fatty acid neutralization in crude oil was achieved by Kieselguhr application. In this process, 9.5% NaOH was applied for 60 min of reaction time. The free fatty acid content of crude oil was decreased from 0.56 to 0.14%, and the remaining soap was found at 34 mg/kg after centrifugation. The use of adsorbents increased the efficiency of NaOH in the neutralization reaction and in the removal of soap from the neutralized oil. Neutralization with support material is a new and promising approach. The application is energy saving, more practical and in accordance with the strict environmental legislation about waste disposal.