Since the turn of the millennium User Experience (UX) has emerged in the field of human computer interaction as an extension to the classical concept of usability. This new approach tries to grasp the user’s experience as whole also considering factors beyond the usefulness of a product, such as pleasure derived from the interaction with it. Given the fairly young age of the field, scientific tools for accurate measurements are still rare and a lot of questions are brought up when it comes to the quality of the current scientific tools used in the field of UX (Bargas-Avila & Hornbaek, 2011). The goal of this Bachelor’s thesis is to take a closer look at two commonly used questionnaires in the field of UX and compare them both with each other as well as with theoretical literature on scale development and questionnaire construction. In a first step, the two questionnaires VisAWI (Moshagen & Thielsch, 2010) and AttrakDiff (Hassenzahl, Burmester, & Koller, 2003) will be examined closer in terms of their development and validation process. These particular questionnaires were chosen because they both aim to measure UX in one form or another, their authors tried to construct and validate the questionnaires in a scientific way, and they are now available online for use by both researchers as well as practitioners (www.AttrakDiff.de; www.VisAWI.de). This means that even if their specific focus is different, the VisAWI’s focus lies on aesthetics while the AttrakDiff focuses on the pragmatic and hedonic aspects of the user’s experience, their overall goal is to make accurate scientific measurements in the field of UX. In a second step, the two questionnaires will be compared, both with each other as well as with the best practice for questionnaire and scale development and validation as presented in current scientific literature. In the end, the goal would be to have a better understanding of what it takes for a scientific instrument to be created and whether or not the two scales in question meet the criteria.