BACKGROUND: Accidents in the construction industry are a significant problem in many countries around the world. Occupational accidents result in reduced working hours, loss of life, and other related costs. These accidents result in socio-economic losses such as disability support costs, loss of working time, and increased medical care needs. They also create a lot of waste for communities and labor organizations. Objectives: Despite extensive studies calculating the cost of accidents, our understanding of these costs is still not clear or practically applicable; consequently, the ultimate aim of the present study is to provide a new framework for the calculation of the (direct and indirect) costs of construction accidents. Methods: In this paper, using a new and structured seven-step approach, the costs of construction accidents were calculated. In order to calculate the total cost of construction accidents in the city of Tehran for 2013 - 2014, the severity of accident results were first classified into five groups: 1, short-term absences from work; 2, long-term absences; 3, partial disability; 4, total disability; and 5, death. The types of costs resulting from accidents were also categorized: 1, production disturbance costs; 2, human capital costs; 3, medical costs; 4, administrative costs; 5, transfer costs; and 6, other costs. These costs were classified according to the direct or indirect costs resulting from the incident and the imposition of costs on workers, employers and society. Finally, the calculated amount of investment in HSE-MS was analyzed using statistical tests. Results: The present study indicates that before and after the establishment of HSE-MS that the maximum calculated cost was related to the production disturbance cost (before: $568,000; after: $80,500) and the lowest cost was related to transfer costs (before: $15,000; after: $3,000) and other costs (before: $98,000; after: $28,500). Statistical analyses indicates that there is a significant difference (P =.007) between the direct and indirect costs of accidents for before and after the establishment of HSE-MS. In other words, the direct and indirect costs had multiple, significant differences. The present study indicates that the indirect cost is four times greater than the direct costs. Conclusions: Accidents resulting in death, total disability and partial disability impose huge costs that are borne by society, and employers bear relatively low costs due to the health, treatment and welfare systems provided by society for the treatment and rehabilitation of injured workers and their families. Also, the results of this study show that investment in the HSE-MS is effective and associated with reduced accidents. Keywords: Accidents; Indirect Costs; Direct Costs; HSE-MS; Construction Industry Language: en