Health surveillance initiatives targeted at populations evacuated from, and residing in, areas affected by radiation contamination were implemented by international institutions as well as national and local governments after the nuclear accidents of Chernobyl and Fukushima Dai-ichi nuclear power plants. Most of these initiatives included a component of childhood thyroid cancer monitoring, with the more comprehensive schemes corresponding to national programmes of health monitoring for adults and children around general health and wellbeing. This article provides a short overview of available data on the costs and resources associated with surveillance responses to two recent nuclear accidents: Chernobyl and the Fukushima Dai-Ichi nuclear plant accidents. Moreover, because the balance of costs and benefits of health surveillance after a nuclear accident can influence decisions on implementation, we also present a brief overview of the principles of economic evaluation for collecting and presenting data on costs and outcomes of a surveillance programme after a nuclear accident. We apply these principles in a balance sheet analysis of a post-accident ultrasound thyroid screening programme for children.