This study examined the factors influencing pre-service teachers' perceptions of computers' self- efficacy. Participants in the study were 305 pre-service science teachers at a four-year public university in Turkey. Two instruments were used for this study: the Turkish version of the Microcomputer Utilization in Teaching Efficacy Beliefs Instrument in a Science Setting (MUTEBI) and a questionnaire for collecting demographic information. A multiple regression analysis was conducted to examine the degree of association between the outcome variables (perception of personal self-efficacy in teaching with computers; perceptions of outcome expectancy) and the explanatory variables (personal use of computers, educational use of computers, level of computer use, grade level, school year, number of computer-related courses taken, age and gender). The findings of this study reveal that level of computer use and educational use of computers are closely related to the outcome measure of pre-service science teachers' personal self-efficacy in teaching with computers. Such findings can help researchers, teacher educators and education programs in assisting pre-service teachers to develop their personal efficacy and their outcome expectancies. (Contains 6 tables and 1 footnote.)