Alveolar hemorrhage syndromes (AHS), caused by a group of heterogenous disorders, are characterized by the presence of widespread hemorrhage into alveolar spaces from damaged alveolar septa, leading to dyspnea, hemoptysis anemia to evaluate the diagnostic and therapeutic, anemia and bilateral alveoler infiltrates on chest radiograph. This study was aimed to evaluate the diagnostic and therapeutic methods and underlying etiological factors of these rare syndromes. Eleven patients (8 male, 3 female, mean age 40±17 years) diagnosed as AHS were investigated retrospectively. In addition to the clinical, serological and radiological investigation, the patients were diagnosed by bronchoalveolar lavage (BAL), transbronchial lung biopsy (TBLB), post-mortem lung biopsy (PMLB) and sputum examination. The underlying diseases were Good-Pasteur (G-P) syndrome, microscopic polyangiitis (MP), Behçet’s syndrome, systemic vasculitis, idiopathic pulmonary hemosiderosis (IPH), warfarin overdose and pulmonary hypertension due to mitral stenosis and chronic renal failure (CRF). The patients with Behçet’s disease and systemic vasculitis were treated with pulse steroid, the patients with G-P and MP had pulse cyclosphosphamide, oral steroid and plasmapheresis was performed, the patient with warfarin overdose was treated with steroid, fresh plasma and K vitamin, the patient with IPH had oral steroid, the patient with chronic renal failure was placed on hemodialysis and had desmopressin treatment. Six patients presented with acute respiratory failure, four of them requiring mechanical ventilation. Seven patients (64%) were died in spite of treatment. As a result, diffuse alveolar hemorrhage (DAH) is a catastrophic complication of a multitude immune and nonimmune disorders, requiring early diagnosis and investigations before respiratory failure develops.