Background: Pain is a common postoperative symptom, and length of hospital stay after surgery is short which highlights the importance of pain assessments. Experiences of assessing pain are mainly described from the perspective of nurses. In postoperative care, enrolled nurses and physicians also assess pain. It is therefore important to take note of their experiences to improve postoperative pain assessments.Objectives: The aim of this study was, through considering critical incidents, to describe care experiences and actions taken by healthcare professionals when assessing postoperative pain.Methods: An explorative design employing critical incidents technique analysis was used. A total of 24 strategically selected enrolled nurses, nurses and physicians employed at orthopaedic or general surgery wards in four Swedish hospitals were interviewed. The intention was to reach variation in age, sex, profession and professional experience.Findings: In pain assessments, patient-related facilitators were patients' verbal and emotional expressions including pain ratings, while lack of consistency with observed behaviours was a barrier. Clinical competence, continuity in care and time were healthcare-related facilitators. The actions healthcare professionals took were gathering facts about patients' pain manifestations and adapting to patients' communication abilities. Patient observations, either passive or active were used to confirm or detect pain. Collaboration between healthcare professionals, including consultations with pain experts, social workers and relatives, strengthened understanding of pain.Conclusions: Communication skills and working conditions have an impact on performance of pain assessment. Patient comfort without compromising safety is reached by including healthcare professionals' dissimilar responsibilities when collecting patients' and relatives' perspectives on current pain.