A rational management of children and adolescents with rheumatic and autoinflammatory diseases requires the regular assessment of the level of disease activity and of child health and well-being through the use of well-validated outcome measures. Ideally, such instruments should be simple and feasible and easily applicable in standard clinical practice. In recent years, a number of novel outcome measures have been developed and validated for use in pediatric patients with rheumatic and autoinflammatory illnesses. Furthermore, there has been an increased focus on the appraisal of child and parent perception of the disease impact. The new tools have markedly enlarged the spectrum of disorders and health domains that can be assessed in a standardized way. This progress will help to enhance the reliability of research studies and clinical trials. The aim of the present review is to provide an update of the recent advances in this field of research.