To study the occurrence of running-related injuries, a group of 115 volunteers were supervised in a training program. These subjects who had limited or no running experience were asked to keep a diary in which they registered information on the training program and injuries. Ultimately, 63% of the diaries fulfilled the criteria for inclusion into longitudinal analysis. The training program (18-20 months) consisted of three phases, each phase finished with a contest (15 km, 25 km, and a marathon, respectively). The participants were individually supervised by an experienced coach with special attention to physiologic training and injury-preventive aspects. Eighty-five percent (n = 62) of the research population sustained at least one injury during the experiment. They reported in total 174 injuries. The number of injury cases per week increased gradually over the experimental period; however, when expressed per unit of exposure time (i.e., 1000 training hours), it showed a decline. There was a significant correlation between the number of injured volunteers and the distance covered during the training at the start of the training program. The anatomic distribution of the injuries is in agreement with findings in the literature. There was also a possible preference for the localization of injuries to the lower leg and Achilles tendon on the left side of the body.