Several novel single nucleotide polymorphisms (SNPs) involved in cytarabine cytotoxicity and related to clinical outcomes have been reported recently in a series of 232 pediatric patients with acute myeloid leukemia (AML). We report the first adult AML cohort in which the influence of these SNPs in cytarabine efficacy and toxicity was analyzed. Six of polymorphisms with clinical significance in the previous study [rs12036333, rs10758713, rs9883101, rs6550826, IRX2: rs2897047, mutated in colorectal cancers (MCC): rs7729269] were analyzed in a cohort of 225 adult patients at initial diagnosis of AML treated with an induction scheme of idarubicin plus cytarabine. The variant alleles of rs12036333 and rs10758713 confirmed the previous associations with lower survival rates. The minor alleles of rs9883101 and rs6550826 were also related to lower survival, in concordance with higher cytarabine-induced cytotoxicity observed in pediatric patients. However, discordant findings between AML adult and pediatric population were observed with IRX2 rs2897047, showing higher survival in heterozygous genotype carriers. The heterozygous genotype of MCC rs7729269 was associated with higher cytarabine-induced toxicities (renal, hepatic, lung, skin toxicities), whereas lower time to thrombocytopenia recovery was associated with the MCC rs7729269 minor allele. This study confirms the influence in survival rates of these polymorphisms in an adult AML population. Novel associations between MCC SNPs and cytarabine toxicities were reported and should be validated in prospective studies involving larger groups of patients.