Early mobilization is essential for patients with multiple long bone fractures associated with other injuries in order to avoid complications. Therefore, in 1969 we adopted a policy of rigid internal fixation of long bone fractures in such cases. To assess the results of this active treatment a number of consecutive patients were followed. The following conditions were necessary for the case to be included in this series: multiple injuries; treatment at the intensive care unit; and at least two long-bone fractures treated with internal fixation. During the period from 1969 to 1974 47 patients met all requirements. With primary operative fixation of long bone fractures of patients with multiple injuries it was possible to mobilize on crutches 29 patients out of 47 within 2 1/2 months of the accident, and 32 were allowed to leave the hospital within 3 months. With the exception of the death of an 80-year-old woman, no severe complications attributed to the operative treatment of these fractures occurred and 32 out of 47 patients returned to work within 16 months. The results in these 47 cases show that in patients with multiple injuries associated with several long bone fractures, primary internal fixation is preferable to the more conventional conservative methods.