Stress fractures in adults are a well described and frequently observed overuse injury with good clinical outcome. In adolescents, stress fractures are very rare and there are only few studies devoted exclusively this type of injury in patients with immature skeletal system. Prognosis of stress fractures in adolescents mainly depends on early diagnosis and early initiated therapy. The object of the present study is to describe typical clinical symptoms as well as characteristic radiological findings in adolescent patients with stress fractures. Thirty-five patients with a total of 40 stress fractures affecting bone with the growth plates still open have been included in the present study. The average duration of follow-up was 4.7 years (standard deviation +/- 2.45, with a minimum follow of 12 months). The average age at occurrence was 12 years (SD +/- 4.31). At initial presentation, pain at exposure was declared as cardinal symptom in 19 of 40 cases, while pain at rest has been described in only 9 cases. An additional swelling has been noticed in 12 cases. Nevertheless, all patients described pain as their major complain. Conventional radiography was unconspicious in 12 of 40 cases; periost hypertrophy was found in 14 cases, while in further 14 cases a fracture line could be detected in conventional radiography. In all cases, in which a magnetic resonance imaging (MRI) has been conducted, changes in signal intensity were detected (including all cases of unconspicous x-ray). Our data indicate, that especially in young sportsmen with pain at exposure of the lower extremity, even if conventional radiography does not reveal abnormalities, MRI should be conducted to detect stress fractures of the juvenile skeletal system in early stages. Only if diagnosis is made early, consistent therapy can be applied as early as needed in order to achieve good clinical results.