The aim of this study was to discover Swedish child healthcare (CHC) nurses' experiences of language assessment in children who do not have Swedish as their mother tongue. A CHC nurse has qualifications in child health, and their role is to promote good health and prevent illness. As immigration to Sweden is at the highest level ever recorded (Statistics Sweden, 2014), there is an increasing need for language assessment. In this study, ‘mother tongue’ is defined as the language a child learns first, which is synonymous with the term ‘first language’ (Oxford Learner's Dictionaries, 2016). The CHC nurses in this study were Swedish-speaking, but conducted speech and language assessments among children who did not speak Swedish; for example, who had a mother tongue other than Swedish. It is important to acquire knowledge of CHC nurses' experiences of language assessment.