One of the challenges today in human–computer interaction is to design systems that are not only usable but also appealing to users. In order to contribute to meet this challenge, our general objective in the present study was to enhance current understanding of the perceptual features that favour users’ interactions with Websites. This is a particularly important issue, as users’ first impressions when they land on a site determine whether or not they stay on it. We conducted two experimental studies, focusing on one specific perceptual feature: Website colour. The first study investigated designers’ and users’ preferred colours for a Web homepage. Although researchers generally flag up differences between designers and users, we found that the latter also had several favourite colours in common. On the basis of these initial results, three colours were selected for a second study exploring colour in relation to an entire Website. The main originality of this second study lays in the fact that we used both subjective and objective measurements to gauge the impact of colour, analyzing not only users’ judgments but also their Website navigation and the items of information they memorized. Results of this second study showed that colours were a determining factor in the way that users interacted with the Website. Their influence was also observed afterwards, when users were asked to exploit the information they had gleaned from the Website. As such, these findings will have a practical value for Website designers.