Starting in the early years of education, math anxiety is negatively related to mathematic outcomes, therefore there is a need for its adequate measurement in young children. This study presents the psychometric properties of the modified Abbreviated Math Anxiety Scale for Elementary Children (mAMAS-E) for first- to third-grade children based on mAMAS. The validity of mAMAS-E was determined by a series of tests. The analysis confirmed its two-factor structure (Testing and Learning), positive relationships between mAMAS-E and math, general, and test anxiety, and a negative relationship with mathematical achievement. Children with a high level of math self-esteem and math self-confidence (but not Polish language self-esteem and self-confidence) have lower math anxiety in comparison to those with a moderate level. The results also indicate that girls have a higher level of math anxiety than boys. The validity and internal consistency of mAMAS-E are satisfactory; therefore, mAMAS-E may be a recommendable questionnaire for measuring math anxiety in young children.