The purpose of this study was to examine the effects of webquest-based applications on the pre-service elementary school teachers' motivation in mathematics. There were a total of 202 pre-service elementary school teachers, 125 in a treatment group and 77 in a control group. The researcher used a Likert-type questionnaire consisting of 34 negative and positive statements. This questionnaire was designed to evaluate a situational measure of the pre-service teachers' motivation. This questionnaire was used as pre- and post-tests in the study that took place in two semesters. It was administered to the participants by the researcher before and after the instruction during a single class period. The paired-samples t-test, the independent-samples t-test and analysis of covariance with [alpha] = 0.05 were used to analyse the quantitative data. The study showed that there was a statistically significant difference found in participants' motivation between treatment and control groups favouring the treatment group. In other words, the participants who designed the webquest-based applications indicated positive attitudes towards mathematics course than the others who did the regular course work. (Contains 2 tables.)