Research is lacking on factors influencing nurses' decision-making directed at the diagnosis of pain in children and its related interventions. This paper reports on two studies, namely a qualitative study and its replication, in which we explored factors influencing nurses' pain assessments and interventions in children. Those factors found to influence nurses' decisions were: medical diagnosis, child's expressions, age, and parents, and the nurses' knowledge, experience, attitude and workload. Some of these factors seem to have more influence than others. For example, the presence of a medical diagnosis seems to legitimate being in pain. Furthermore, it is suggested that mainly vocal expressions, especially crying, influence nurses' decisions to administer analgesics. Finally, nurses' negative views on non-narcotic analgesics were striking. In this paper, the results of both studies and their relationship to information reported in the literature are further elaborated and discussed, and hypotheses on strength and direction of influence of factors on pain assessment and intervention are generated.