Students perform intensive web-based applications during their education. One of these is project-based application. In this study, the effect of web based project applications on students’ attitudes towards chemistry has been investigated. 42 students attending Hacettepe University, Faculty of Education, and Department of Chemistry Education have been participated in these applications. Attitude Scale towards Chemistry has been administered before and after applications. The application has been started with displaying the chosen simulation experiments with the computer program called CCI-Project (Creative Chemistry on the Web) ETH (Eidgenossische Technische Hochschule-Zurich). When the simulation experiments have been displayed, students have been assigned in groups of 3-4 randomly. Totally 11 Web Based Projects have been prepared. Each of the teams has determined a project question related to their given simulation experiment. When teams have completed their projects, they have presented them by using power-point. Researchers have videotaped project presentations. After presentations, project presentations have been displayed consecutively and discussed in class. Researchers have evaluated each team’s projects by “Project Sufficiency Form”. While students’ scores of Project Sufficiency Form have been accepted as their project performance, both their final grades and project performance score have been accepted as student performance. Using paired-samples t-test has compared pre- and post-test results of attitude scale and a statistical difference has been found. Also a relationship between students’ attitudes and performance has been examined by using regression analyze.