Both upper gastrointestinal endoscopy and colonoscopy are recommended in men and post-menopausal women with iron deficiency anemia. Due to lack of data on the yield of these endoscopies in young men, they are currently investigated as older men. The aim of this study is to evaluate prospectively the prevalence of various gastrointestinal lesions in young men with iron deficiency anemia. Our hypothesis is that the diagnostic yield of colonoscopy in young anemic men without gastrointestinal symptoms is very low, especially if a potential lesion is detected during upper gastrointestinal endoscopy. Therefore, this study will try to identify predicting factors regarding the yield of both endoscopies. Another purpose is to evaluate the outcome of patients with negative endoscopic results, during a follow-up of two years.