Due to the COVID-19 epidemic, courses are carried out online in undergraduate programs and in this study, Web-Based Intelligent Tutoring System (WBITS) was used for online lessons. The aim of the study is to determine the opinions of 144 pre-service science teachers, who have used WBITS in three different undergraduate courses, about the system. Opinions about whether they are happy to use WBITS, whether the system serves the purpose of the courses (validity), whether the system is an alternative to face-to-face education (reliability) and whether the system is sufficient in pedagogical aspects (pedagogical qualification) were collected. The majority of the candidates stated that they are happy to use the system, that the system can be used to achieve the course objectives, and that the system is pedagogically sufficient and it can be used instead of the traditional classes. The most positive opinions were that the lesson could be used to achieve the course objectives. Negative opinions about the use of the system were mostly related to being unhappy with using the system. The system can be adapted for different courses and can be used in distance learning processes or to support in-class education. The system can be effective in overcoming the limitations of distance education.