This article discusses the use of adjustments in the context of enhancing the comparability of pan-European comparables searches for transfer pricing purposes. The authors analyse technical challenges encountered when performing comparables searches and adjustments in practice, and address issues that require further guidance in the process of developing a harmonized approach to comparables searches from a pan-European perspective. A general background is provided regarding how adjustments comply with the arm's length principle, along with examples of technical issues and best practices related to the application of adjustments.