The assent procedure reflects an effort to enable the minor to understand, to the degree they are capable of, what their participation in the decision making process would involve. Aims: To evaluate the minors’ ability to understand the information provided to them when obtaining assent and to evaluate the opinion of the parents regarding the importance of asking the child’s assent. Methods: The sample included a total of 52 minors aged between 10 and 17 years who underwent exercise echocardiogram. The Quality of Informed Consent is divided into two parts: Part A was used to measure objective understanding and part B to measure subjective understanding. Results: The results show that the minors have a high capacity to understand the information given to them when asking for assent. A positive relationship was found between the two parts of the questionnaire. No statistically significant relationship was found between age and sex and part A and part B or between both age groups (<14 years old and ≥14 years old) and the measure. In the case of the parents, 96.6% of parents consider assent as an advantage for the child’s acceptance of health care. The opinion of the parents is not related to the age, sex or level of schooling. Conclusion: Minors showed a substantial level of understanding regarding the information provided to them. The parents considered the implementation of assent fundamental to the child’s acceptance of health care.