Background and Objectives: The health care professionals’ knowledge on chronic noncancer pain in pediatric age may have implications in clinical practice, and eventually impact on patients’ health-related quality of life. However, there are no research studies in Portugal addressing that issue. Our main goals were to study health care professionals’ knowledge on chronic noncancer pain in pediatric age, as well as associated variables, namely sociodemographic and professional variables, perception of knowledge, and behavioral attitudes regarding chronic noncancer pain in pediatric age. A self-report questionnaire was developed to evaluate the variables under study. Methods: 66 doctors and 71 nurses (N = 137) practicing with pediatric patients completed a self-report questionnaire in order to evaluate: knowledge on chronic noncancer pain (“definition/epidemiology/pathophysiology”; “psychosocial aspects”; “pain assessment”; “pharmacological treatment” and “non-pharmacological treatment”), sociodemographic and professional variables, perception of knowledge, and behavioral attitudes regarding chronic noncancer pain in pediatric age. Results: The overall level of health professionals’ knowledge on chronic noncancer pain at pediatric age is moderate (M = 65.69; SD = 11.01) [0-100]. The highest scores were in "psychosocial aspects" and "non-pharmacological treatment" subscales; the lowest scores were in "pharmacological treatment" and "definition/epidemiology/pathophysiology" subscales. In addition, our results showed that the overall level of knowledge is related to the perception of knowledge (namely, awareness of pediatric pain assessment national guidelines, and perceived ability to apply pain rating scales in pediatric age), as well as behavioral attitudes (namely systematic pain assessment and recording at an appointment with a pediatric patient, as well as performing etiological assessment in the medical approach of patients with chronic noncancer pain). Conclusions: Our data support the relevance of developing training programs focused on promoting health care professionals’ knowledge on chronic noncancer pain in pediatric age, pointing out areas in which such programs should be focused.