The aim of this work was to assess the relationship of both total alkaline phosphatase (ALP) and bone-specific alkaline phosphatase (BsALP) with the course and outcome of operatively treated long-bone fractures. The activity of total ALP and BsALP was measured in 41 patients with a long bone fracture, comprising 26 men and 15 women. All patients were treated operatively. Total ALP and BsALP levels were measured in sera on day 1, 7, 14 and 21 after sustaining injury. Patient monitoring included X-rays. According to the outcome, patients were divided into two groups: the fast healing group and the slow healing group. The levels of total ALP and BsALP showed parallel trends in the course of this study. Depending on the healing outcome, on day 7 an increase in the case of slow healing, or a decrease in the case of fast healing, for both BsALP and total ALP was observed. No difference was found between various sites of bone fracture. This is an important result indicating the prognostic significance of total ALP and BsALP measurement in the monitoring of long bone fracture healing. In addition, an early change in the level of these enzymes was associated with the efficiency of the performed surgery.