The main task of contractors' estimators is to predict the likely costs involved in executing a future project. This is an onerous job as any errors made can undermine project success and ultimately reduce the contractors' profit margins. The inherent uncertainty of most construction work, however, together with the often very short time periods involved, make errors unavoidable. Unsurprisingly, therefore, estimation is considered to be a very stressful business. To identify the nature of the stress involved, a survey of construction estimators in Hong Kong was conducted. Using correlation analysis, regression analysis and structural equation modelling, the relationships amongst the causes (stressors or stress factors) and effects (stress) were examined and a causal structural model developed. The results indicate work overload, role conflict, job ambiguity, and working environment to be the most critical stressors, with work underload and distrust being the main indirectly influencing factors. These results are similar to those of a previous study with site managers, suggesting that job ambiguity and work overload are the common problem in the construction industry. The study of the manageability of stress is expected to inspire other similar research involving other professionals in the construction industry. This is expected to be of particular significance in the long-term development of stress management in the industry in general.