The importance of accounting for human resources has long been recognised by the Accounting profession. Until recently, Human Resource Accounting (HRA) literature has been dominated by discussion as to whether humans fit the traditional definition of assets, and how to measure and report them. We investigate the concept of human capital and its measurement through a review of the HRA literature, as well as the literature in Human Resources (HR). This paper then draws on the findings of a small exploratory study into the measurement of Return on Investment (ROI) for international assignments. Interview data reveals that intangible costs and benefits are problematic when applying such a metric; that much of the outcome from the assignment is intellectual capital, in its broad sense, and therefore difficult to isolate and effectively measure.