Despite the existence of protocols for effective pain control, pediatric pain is still high, due to scarce knowledge of its treatment, especially regarding opioids. This study aimed to evaluate doctors and nurses' knowledge of pain treatment and the use of opioids in children, before and after the implementation of Law 38/2010, that represented an important step in guaranteeing patients' rights to gain access to appropriate services for pain control and palliative care in Italy and in establishing the obligation of specific training programs in this matter for health professionals. An ad hoc questionnaire was developed and administered before (investigation A) and after (investigation B) the issuance of the Law. In B both doctors and nurses showed a slight but significant increase in correct answers and a reduction in incorrect ones, mainly concerning the category Myths and Prejudices. In both investigations doctors and nurses showed adequate general knowledge, yet there were some gaps regarding the specific knowledge of opioid drugs. Most of the participants were not familiar with the Law and its provisions.Investigation B showed an improvement in health professionals' knowledge, perhaps due to a hospital environment that followed the provisions of Law 38/2010. Nevertheless, the establishment of training courses according to the Law is needed to improve the knowledge of opioids, as well as to dispel deeply rooted myths and prejudices on pediatric pain.