Pyrimidine-5-nucleotidase (P5'N-1) deficiency is a rare nonspherocytic hemolytic anemia due to pyrimidine nucleotide deposition within erythrocytes. This rare erythrocyte disorder shows autosomal recessive inheritance with mutation of the pyrimidine-5'-nucleotidase gene, which is localized on 7p15-p14. Consanguinity of parents increases the probability of disease with novel mutations. Here, we report a 12-year-old boy with a delayed diagnosis of P5'N deficiency whose parents were consanguineous. He had a hemoglobin level of 7.5 g/dL, mean corpuscular volume of 93 fL, 7% reticulocyte, and lactate dehydrogenase of 678 IU/L. A peripheral blood smear showed polychromasia, marked anisopoikilocytosis with schistocytes, elliptocytes, stomatocytes, spherocytes, dacryocyte, and basophilic stippling in red blood. Decreased purine/pyrimidine ratio was 1.07 (normal range=1.4 to 2.98). Molecular analysis with direct DNA sequencing of the NT5C3 gene, codifying for P5'N-1, revealed the presence of a novel homozygous mutation, c393-394delTA, in the gene coding P5'N enzyme in the patient. To our knowledge, this is a newly defined mutation in P5'N deficiency.