Several genetic association studies have evaluated the associations between ALL and MTHFR gene polymorphisms in various populations and produced contradictory or inconclusive results.11-14 The present study aimed to find out the possible association among rs1801131 (A1298C), rs1801133 (C677T) and rs13306561 polymorphisms in the MTHFR gene and ALL risk in a sample of the Iranian population. The gene discussed is MTHFR; the disease is acute lymphoblastic leukemia.