To examine nurses' and physicians' assessments of pain in children with cancer, and to identify the methods in use to diagnose, evaluate, and treat pain. In addition, to examine whether/how the healthcare professionals' assessment and management of pain has changed compared to 1995 and identify the needs for training. The study has a descriptive and comparative design. 363 nurses and physicians working with children with cancer in Sweden were invited to participate in April 2017. Participants answered an updated version of a questionnaire used in 1995 by Ljungman et al. focusing on the healthcare professionals' experience of pain among their patients, their pain treatment strategies, and need for training. 120 nurses and 65 physicians participated. Fifty percent of nurses and 55% of physicians answered that moderate-to-severe pain was experienced often or very often by children with cancer. Methods recommended in international guidelines to diagnose, evaluate, and treat pain were generally followed. Compared with findings from 1995 by Ljungman et al., nurses, and physicians assessed that moderate-to-severe pain was seen more often. The greatest need for training was reported for pharmacology, different routes for administration of opioids, treatment with nitrous oxide, and nonpharmacological interventions. Nurses and physicians assessed that moderate-to-severe pain is often present in children with cancer. More time to treat pain in the department and training in certain areas seem to be needed to improve pain management.