Through practices of assessment and consultation, information gathering and analysis, social workers, in the field of child protection, build understandings about children and families. Social workers actively construct knowledge as they engage in assessments of children referred to them as potentially 'at risk'. Their work is always informed by explicit or implicit theories about risk and protection. The active engagement with risk by social workers is the central focus for this inquiry. This thesis presents an exploratory inquiry into the work of child protection in Aotearoa/New Zealand as experienced by social workers employed at the Department of Child, Youth and Family Services (CYFS). The primary focus is on their understanding of risk and their active construction of risk discourses. I am interested in how children are identified as potentially at risk, and how risk is identified, worked with, managed and woven into the assessments of social workers as they engage in child protection work. This inquiry took, as its starting point, narratives of 70 social workers about specific child protection cases. They were asked to describe both straightforward and more complex assessments, and, as a result, provided a rich and detailed range of narratives about how risk is defined, assessed and managed by social workers. This qualitative study employed a critical incident technique as a data collection method, and applied a grounded approach to the analysis of these practice stories. The focus for the interviews was on the day-to-day work as experienced by social workers, that is, the practices of assessment in child protection. Probes were used to solicit further information when risk was discussed by the workers. This research also involved spending time in different branches of CYFS around the country and informal conversation with social workers. Field notes made during these periods of immersion in different practice settings were also analysed to provide understandings of the contexts in which social workers engage in individual and collective knowledge production about children and risk. This is the first detailed investigation of how New Zealand statutory social workers of different ethnicities engage with, and draw on, risk discourses in their assessment work. For the social workers in this study, risk discourses were actively and strategically used in the legitimation of their practice interventions. The practices of socially constructing knowledge about 'risk' are a continuing focus of this thesis, and the wider implications for social work practices of 'risk' assessment are discussed.