BACKGROUND AND AIMS: The etiology of iron deficiency (ID) without anemia in young men is unclear, and there are no evidence-based recommendations for the required gastrointestinal (GI) evaluation. The aims of this study were to examine the incidence of significant GI pathology and the development of anemia during the follow-up of young men presenting with ID, but without anemia. METHODS: All young men (18-30 years) who served in the Israel Defense Forces during the years 2005-2013 and had at least a single laboratory test indicative of ID without anemia were followed until the diagnosis of significant GI pathology or discharge from military service. RESULTS: The study population included 2061 young men (mean age 20.7+/-1.8). During follow-up of 3150 person years, significant GI pathologies were diagnosed in 39 patients: inflammatory bowel disease in 25 (1.2%), celiac disease in 8 (0.4%), and peptic disease in 4 (0.1%). No cases of GI-related cancer were diagnosed. ID anemia developed during follow-up in 203 (9.8%). Lower baseline hemoglobin levels, lower ferritin levels, and younger age at diagnosis were more common among those who developed anemia. The development of anemia was a predisposing factor for the diagnosis of GI pathology (risk ratio=3.60, 95% confidence interval 1.34-8.32, P=0.012). CONCLUSION: Significant GI pathology is very uncommon in young men presenting with ID. Overt anemia developed in close to 10% of the study cohort. Therefore, we advise simple GI evaluation (celiac serology, C-reactive protein or fecal calprotectin, and urease breath test) as well as follow-up in this population.