Background: Preverbal children are at increased risk for underassessment of pain. Pain is a social transaction involving the child in pain and the nurse assessor. However, our understanding of the nurse's part in this transaction is limited. Aims: The aim of this study was to explore nurses’ assessment of pain in hospitalized preverbal children based on self-selected clinical examples. Design: Qualitative, descriptive design. Settings: Five different hospital units in Canada and Norway. All units had an observational pain scale for preverbal children available for use. Participants/Subjects: Nurses (N = 22) with ≥1 year experience caring for preverbal children. Methods: Individual, semistructured interviews. Data were analyzed using inductive thematic analysis. Results: Nurses' assessment of pain in hospitalized preverbal children emerged as a nonlinear complex process incorporating different actions and reflections in response to the child's situation and expression of distress. Information from parents was routinely included in the assessment, although further parental involvement varied considerably. Although each assessment was personalized to the individual child, the nurse used previous experiences to interpret observations of and information from the child and the parents. Few nurses described using structured pain scales, but when used, these scales were included as only one aspect of their overall assessment. Conclusions: Nurses preferred pain assessment based on clinical judgment and tailored to the individual child. Implementation strategies that aim to integrate structured pain scales with clinical judgment to assess pain may be more likely to succed. Further examination of this approach is warranted.