This study investigates the impact of using the heuristic teaching approach for teaching mathematics to tenth grade students in Jordan. The researchers followed the equivalent pre/post T test two group designs. To achieve the goal of the study, a pre/post- test was constructed to measure student achievement in mathematics. The sample for this study consisted of 142 students; 69 male students and 73 female students from tenth grade at King Abdullah School in Irbid, Jordan for the first semester of the academic year 2011/2012. The subjects of the study were distributed into an experimental group and a control group. The experimental group was taught mathematics using the heuristic approach while the control group was taught mathematics using the traditional method of teaching. The subjects were 34 male students for the experimental group and 35 male students for the control group, while the female students for the experimental and control group were 37 and 36 respectively. Those subjects were distributed into two purposefully selected sections at king Abdullah School in Irbid. Descriptive statistical analyses were used (means and standard deviation) for the pre- and post- tests of students. Comparison statistical methods were used (Two Way ANOVA) analysis of variance to make a comparison between the control and the experimental groups and gender variable. The findings of the study indicated that there were statistically significant differences in the post- test between the control and the experimental groups in favor of the experimental group, and there was no statistically significant difference in the students' achievement due to gender. There was no statistically significant difference due to the interaction between gender and group. The researcher proposes some recommendations to enhance the effect of using heuristic approach in teaching mathematics on students' performance such as conducting further studies in other universities. (Contains 4 tables.)