AbstractThe assets and drawbacks of ISS are documented, utilising 2 groups of patients with blunt multiple trauma. Group I consisted of 80 patients with 417 fractures and 163 major associated injuries. Group A had early fracture stabilization and prophylactic ventilation, Group B had early fracture stabilization without prophylactic ventilation, Group C had delayed fracture stabilization and prophylactic ventilatory support. Utilising the ISS, subgroups of A and C were constructed that had injury severity scores ≥ 50 (means 57 and 58.7) containing 19 and 11 patients. Group A had a 10% mortality rate, a late sepsis mortality rate of 6%, and ARDS incidence of 26%, and a mean duration of ventilation of 6 days, while group C had a late sepsis mortality rate of 55%, and ARDS incidence of 82%, and a mean duration of ventilation of 26 days. It is concluded, that early operative stabilization of fractures is safe, and in significant part is associated with a reduced number of late sepsis deaths while reducing the duration of ventilator support required, and that prophylactic ventilator support (i.e., continued support after surgery significantly reduces the incidence of ARDS).Group II consisted of all blunt trauma patients with an ISS greater than 20, admitted during 1981. Sixty‐eight patients were admitted and the correlation was sought between ISS and mortality. It was concluded, that death exclusively from central nervous system injury should be analyzed separately from death from other causes in multiply injured patients. Reference is made to other applications of ISS than the documentation of mortality and suggestions are made for improving ISS by including the Glasgow‐coma scale and including patients related risk data. A plea is made to devise a standard method for ISS calculation.