Occupational accidents may incur considerable financial losses for companies. The purpose of this study was to investigate the financial losses incurred by building contractors in Singapore due to construction accidents. A questionnaire survey was used to collect data for this study. The results show that the average insured accident costs, average uninsured accident costs and average total accident costs account for 0.15%, 0.1% and 0.25% of the contract sum of a project, respectively. The ratio between insured and uninsured accident costs for building projects was found to be 1.5:1. Furthermore, company size, project size, and percentage of work completed by subcontractors were found to have impact on the size of uninsured costs of accidents. In light of this study, Singapore contractors may be more conscious about the financial implications of construction accidents, which would in turn motivate contractors to prevent construction accidents.