Introduction: Differences in baseline characteristics and response to treatment in different age groups of patients with chronic myeloid leukaemia (CML) in resource-limited countries have not been extensively studied. We aimed to determine the differences in clinicopathological parameters at diagnosis and response to imatinib in adult CML patients with younger (under 60 years; YCML) and older (60 years and older; OCML) age treated at our institution from March 2001 to March 2021. Methods: A retrospective analysis of consecutive adult CML patients receiving imatinib was performed. Clinicopathological parameters and treatment response were reviewed and analysed using hospital medical records and electronic data reports. Results: The median age at diagnosis was 50 years. OCML patients (n=17) had significantly more comorbidities. The YCML group (n=50) generally had a palpable spleen >5cm from the costal margin, mild anaemia, hyperleukocytosis and thrombocytosis. A starting dose of 400 mg/day was observed in 84% of YCML and in 65% of OCML. Cumulative complete cytogenetic response was 50% in YCML versus 70.6% in OCML, p=0.158. OCML tended to have a higher percentage of major molecular response (MMR) (52.9% versus 32%) and a shorter time to MMR, 22 months (range 5-70) versus 35 months (range 8-53). OCML experienced more haematological and non-haematological treatment-related adverse events after imatinib therapy. Conclusion: Although OCML patients had more comorbidities and treatment intolerances, overall long-term treatment response was comparable to YCML. In OCML, a more personalised approach to initial and subsequent dosing of imatinib may be considered.