The performance of elements and complying with choreography rules in rhythmic gymnastics greatly depends on ambidexterity. Most rhythmic gymnastics athletes, even elite ones, have troubles when need to use the non-dominant hand/leg/side of the body. Aim: This study aimed to determine to which extent does rhythmic gymnastics beginner's training develop the relationship between the right and left side of the body (ambidexterity) using a 6- month standard training process. Methods: The sample consisted of 40 participants (7-9 years old). New measuring instruments were designed to assess the degree of acquisition of specific techniques (5 in total, one for each apparatus). The athletes demonstrated the techniques with their dominant and then non-dominant side of the body and were videotaped. Three experienced judges made an assessment based on the videotaped material and the coefficients of asymmetry were calculated for each technique according to the prescribed formula. Results: The obtained reliability parameters have shown that the analyzed tests with the corresponding criteria are a reliable measuring instrument and can be used to evaluate the ambidexterity in novice gymnasts. The 6-month standard training process numerically improved the total ambidexterity, although the significant difference was noticed only in the coefficients of asymmetry for the rope technique. Since the rope is one of the apparatus that needs to be handled with both arms and, additionally, is well known to beginners, this result doesn’t surprise. Conclusion: Rhythmic gymnastics training is largely aimed at the equal development of both sides of the body/arms/legs and in these terms has a positive effect on the overall health of the trainee.