The aim of present study was to evaluate the effects of interdisciplinary approach in math performance and in the motivational climate. One hundred and ninety three pupils (97 boys & 96 girls), aged 9-11 years, from 10 different schools, took part in this study. The evaluation was held through questionnaires which the students completed before and after the intervention. Eight interdisciplinary PE lesson plans were designed, combining motor skills and math. The statistical analysis revealed that pupils of the experimental team had statistically significant higher scores in lesson satisfaction, intrinsic motivation, and also in the specific math test. Also, pupils of the experimental group had lower scores in ego orientation, extrinsic motivation and amotivation. The findings of present research imply that an interdisciplinary approach in physical education classes can be possibly applied effectively in combination with the teaching of mathematical principles.