This study examined how CYP2C8*3 (G416A; rs11572080) and ABCG2 C421A (rs2231142) single nucleotide polymorphisms (SNPs) affect the plasma trough concentration and therapeutic response of imatinib in Egyptian CML patients. This evidence concerns the gene CYP2C8 and chronic myelogenous leukemia, BCR-ABL1 positive.