Adequate analgosedation is an essential part of comprehensive care for critically ill children of all ages admitted to pediatric intensive care units. Despite extensive research and progress in this field, there is still a lack of evidence on efficacy, safety, and dosing of analgesic and sedative drugs used in this population. Pain is described by a conceptual model as a subjectively perceived and expressed experience while pain reflects also a basic defense mechanism that protects the body from harmful sensations. However, untreated pain and inadequate analgosedation can have both acute and long-term consequences for the human body. Children admitted to pediatric intensive care units are exposed to many painful and stressful stimuli and subsequent disability due to pain, stress, or current illness is expected. Inter alia, it is known, that children experience pain different from adults, moreover, children’s responses to its treatment may vary among different age groups and drug disposition is highly variable. Hence, various validated assessment instruments and treatment interventions have been developed to achieve adequate analgosedation. Finally, effective and safe analgosedation is also an important indicator of the quality of care from both an ethical and medical perspective, as well as determining short-term and long-term outcome measures.