The applications of multiple intelligence theory in education are wide. Students apply the learning in the classroom according to their own dominant intelligence and learning style, which is most effective for them. Combining learning styles with dominant intelligences enhances the students' learning processes. The purpose of this case study is to examine the relationship between dominant intelligences according to Gardner's multiple intelligence theory and middle school students' academic achievement. A case study was conducted in Israel, in a middle school, among seventh-graders and involved 158 students. Findings indicated that in excellent classes -- 80.9% of students had logical intelligence, in at least one of the levels of dominance; in ordinary classes only 48.4% of students have logical intelligence, at least in one of the levels of dominance. We also examined the relationship between the amount of dominant intelligences among students in all classes, excellent and ordinary. Findings indicated that in excellent classes the percentage of students with two or three dominant intelligences was higher than the percentage in ordinary classes. It is important to note that these are not just the logical and verbal, but also all types of intelligences, such as spatial, musical, kinetic and others. In conclusion, the dominant intelligences that highly influence and measure achievement in the education system are not the logical-mathematical and the linguistic-verbal, but the only logical-mathematical. Moreover, the amount of intelligences at the dominant levels can predict and indicate student's success at school.