Pearson syndrome (PS) is a mitochondrial disease and clinical presentation is rather varied. These patients are often subjected to extensive biochemical and clinical work-up for diagnosis. We report two new cases and review our experience with PS in Hacettepe University. The first case had large deletion of mitochondrial DNA (mtDNA) and presented with severe metabolic acidosis and anemia associated with hemophagocytosis in bone marrow. He also had liver involvement and tubulopathy. The second case, who had the 4997 bp common deletion, presented with anemia at 8 weeks of age followed by an uneventful 4 years. She developed very severe acidosis and renal Fanconi syndrome at the age of 4.5 years. Our cases revealed once more the clinical diversity of the disease and no correlation between the size and site of mtDNA deletion and clinical presentation. We encourage physicians to look for PS in children with early sideroblastic anemia and multiple organ system involvement.