The amplification of telomerase component (TERC) gene could play an important role in generation andtreatment of haematological malignancies. This present study was aimed to investigate copy number amplificationstatus of TERC gene in chronic myeloid leukaemia (CML) patients who were being treated with imatinib mesylate(IM). Genomic DNA was extracted from peripheral blood of CML-IM Resistant (n=63), CML-IM Respond(n=63) and healthy individuals (n=30). TERC gene copy number predicted (CNP) and copy number calculated(CNC) were determined based on Taqman® Copy Number Assay. Fluorescence in situ hybridization (FISH)analysis was performed to confirm the normal signal pattern in C4 (calibrator) for TERC gene. Nine of CMLpatients showed TERC gene amplification (CNP=3), others had 2 CNP. A total of 17 CML patients expressedCNC>2.31 and the rest had 2.31>CNC>1.5. TERC gene CNP value in healthy individuals was 2 and their CNCvalue showed in range 1.59-2.31. The average CNC TERC gene copy number was 2.07, 1.99 and 1.94 in CMLIMResistant patients, CML-IM Respond and healthy groups, respectively. No significant difference of TERCgene amplification observed between CML-IM Resistant and CML-IM Respond patients. Low levels of TERCgene amplification might not have a huge impact in haematological disorders especially in terms of resistancetowards IM treatment.